Well I wasn't going to do this, but after having noticed a couple things on a couple cards, guess I'll go through and give brief opinions on all. Disclaimer: I've never entered any of these contests or even designed a fan card, so these opinions are purely just a feel from having played lots of Dominion.
Lockbox
Types: Action Duration
Cost: $4
Now and at the start of your next turn: +1 Buy.
When you discard this from play, if you do not buy a card this turn, you may set aside up to 3 Treasures from play. At the start of your next turn, put the set-aside Treasures into your hand.
Already commented in its own post; seems like a much weaker version of Tactician, even a much weaker version of Haven. And I'm not convinced that it even works as intended with the rules.
Star Charts
Types: Action Duration
Cost: $5
Now and at the start of your next turn, look at the top 4 cards of your deck, discard any number of them, and put the rest back in any order.
While this is in play, when a player buys a card other than a Victory card, he gains a copy of that card, putting it on top of his deck.
I like the double-Cartographer effect. Quite weak now, but full-Cartographer next turn. And the fact that you get the Talisman twice while your opponents only get it once seems neat. Putting the copy on your deck seems unnecessary. Maybe too strong for $5... compared to Cartographer, you also basically get a free Talisman that's not limited to $4 or less cards. (If you consider the second Talisman as being cancelled by opponent's Talisman).
Shipwreck Cove
Types: Action Attack Duration
Cost: $5
+2 Cards. Each other player chooses a card he has in play and discards it. If that card would do something at the start of that player's next turn, that effect is cancelled. At the start of your next turn, +1 Action.
I like the idea of being able to kill off Durations. Problem is, it's terrible if there aren't other Durations in the game. Also, the +1 action (and the fact that it is a Duration) feels tacked on. Like the only thing it does is ensure there's a Duration in the game.
Harbourmaster
Types: Action Duration
Cost: $5
+3 Cards. You may discard this from play. If this is in play at the the start of your next turn, trash it and +3 Cards.
I like this. Nice Smithy-with-a-bonus. As mentioned above, would probably reword:
+3 Cards.
At the the start of your next turn, you may trash this. If you do, +3 Cards.
Tariff
Types: Action Duration
Cost: $4
+$2. Choose another player. At the start of your next turn, +$1.
While this is in play, when the chosen player buys an Action or Treasure card, you my discard a card. If you do, +1 Card.
As WW mentioned, I'd skip choosing a player. Also seems odd to limit it to buying an Action or Treasure. And it's probably too inconsistent. If someone's playing a big engine and buys several cheap engine pieces on his turn, you get to design the perfect hand. But they might also have a terrible hand and you get nothing. And the discarding-drawing feels tacked on anyway. Card might be just fine without it, though I think it could be $3 then.
Clipper
Types: Action
Cost: $3
+1 Card. +1 Action. Put a Coin token on an Action card pile in the Supply.
Cards cost $1 less per Coin token on their Supply pile, but not less than $0.
Is "Action card pile" well defined? I guess it's clearer than the other card that uses "victory card pile", since all the Knights are actions. Actually... just realized that Trade Route uses "Victory card supply pile." Um, I'm assuming that Knights with Josephine on top doesn't get a token? Is this clarified in the rules? Anyway, I digress. This card doesn't really do anything for you, since your opponents get the same benefit that you do. So why should you be the one to buy it?
Beacon (A)
Types: Action
Cost: $6
+1 Action.
While this is in play, keep the top card of your deck revealed. During your Action or Buy phase, when the top card of your deck is an Action or Treasure, you may discard this from play. If you do, play that card and gain a copy of it.
Is this intended to be a Duration, so that it stays in play until you use it? Either way, it can be discarded mid-turn, meaning you could play the same card again. And it's already been pointed out that this can empty the entire Grand Market pile (or any pile with +1 action.). And allowing to play actions during buy phase is no good, I think.
Cottage
Types: Action Duration
Cost: $3
+2 Cards. +2 Actions. Put 2 cards from your hand on top of your deck. At the start of your next turn, reveal the top 2 cards of your deck. You may discard one of them. You may trash one of them. Put the rest back in any order.
Seems like a stronger version of Inn, except no on-gain part. Usually you'd rather discard 2 cards than put 2 back, but even so. Inn now, safe Lookout later. Probably a $5.
Ship of the Line
Types: Action Duration
Cost: $5
You may gain a Victory card costing less than a Province. At the start of your next turn, +3 Cards.
While this is in play, Victory cards cost $1 more.
Probably too strong. At the start of your next turn effect is a +4 cards +1 action. HUGE. And the green gaining is optional, so you wait until you have a good engine to fire it. Meanwhile playing a couple per turn to slow your opponent.
Investment
Types: Action
Cost: $5
You may choose an Action card from your hand. Set aside this and the chosen card on your Investment mat. Return them to your deck at the end of the game.
When you play an Action card, +$1 per copy of it on your Investment mat.
Setting aside just a Market turns all your Markets into Grand Markets. For most cards, you would probably want to set aside only 2 copies of them, better to have the rest to play. As a whole this could work, but I'm worried it's too strong.
Shipyard (A)
Types: Action Duration
Cost: $4
+1 Card. Now and at the start of your next turn, trash a card from your hand.
The fact that it's mandatory next turn is scary. You don't know what you'll have. Almost a required opener, but quite weak in mid-game when it's risky to play. Might go from too strong to too weak to be a good card.
Fisherman
Types: Action
Cost: $4
+1 Buy. +$1.
When you discard this from play, put one of your Fisherman token on a Supply pile that costs $6 or less which is not a Victory card pile.
When you buy a card, gain a copy of it for each of your Fisherman tokens on that pile and remove all of your Fisherman tokens.
Clarification: Each player has his own Fisherman tokens (maybe in different colors) and you only gain copies of the bought card for YOUR tokens.
I see no reason to force the token delay by making it "when you discard this from play". Probably weak either way. And +1 buy seems weird, since it's getting you extra cards without needing extra buys. Basically a weak Talisman? And why $6 or less? Since victory cards are already ruled out, that only rules out 5 specific cards.
Thugs
Types: Action Attack
Cost: $4
+2 Buys. +$2. Each other player with 4 or more cards in hand discards 1 card for each card he gained last turn. Each other player with no cards in hand draws 3 cards.
Agree with other comments; annoying to remember how many cards were bought (assuming it's meant to say "his last turn" instead of "last turn"). Also too strong; will flat-out stop people from buying more than 1 card per turn, while giving + buy.
Cannon
Types: Action Attack Duration
Cost: $5
+1 Action. +1 Buy. At the start of your next turn, you may trash up to 2 cards that are not Curses. If you trash exactly 1 card, each other player discards down to 3 cards in hand. If you trash exactly 2 cards, each other player gains a Curse.
Don't like attacking next turn. Don't like the non-curse restriction.
Recycle
Types: Action Duration
Cost: $5
Trash a card from your hand. Gain a card costing up to $2 more than the trashed card, setting it aside face down. At the start of your next turn, return the gained card to your hand and trash a card from your hand, gaining a card costing up to $1 more than that trashed card.
Weird. I think I like it. Too strong though. You can use it as an Expand. As was mentioned earlier, gaining a card next turn is usually just as good as gaining it this turn. Meaning it will usually be a full Expand if you want it to be. Plus more flexibility. Also no reason to set aside face down; everyone saw what you gained.
Martello
Types: Action Duration
Cost: $3
Now and at the start of your next turn: +1 Action and +1 Buy.
While this is in play, when any player gains a card, you may choose for him to put that card on top of his deck. If you do, he may first discard the top card of his deck.
EDIT: Changed "when another player gains a card" to "when any player gains a card" on Martello.
On one hand it should be an attack, but it might just be cleaner without that, because it avoids all the rules questions about attack durations; and more often than not it won't be used to hurt opponents anyway. I don't know about the bonuses though. Worker's Villages next turn is pretty strong I'd think.
Kraken
Types: Action Reaction
Cost: $6
+$2. Put a card from your hand on top of your deck.
When you put this on top of your deck, you may reveal it. If you do, choose a card in the Supply; each other player gains a copy of the chosen card, putting it on the bottom of his deck.
Should probably just be "gains a curse" instead of any card of your choice. You'll always choose Curse until they're gone; then you can start giving Estates or Coppers; depending on the game state. Any why bottom of the deck? Seems random and tacked on. Also, needs to be an attack. And finally, it does almost nothing unless you happen to connect 2 of them (or if your combine with Courtyard or opponent's Ghost ship). So in general this is a more expensive Mountebank who's attack misses more often. Weak, but the unlimited junking potential means long boring games.
Flagship
Types: Action Duration
Cost: $5
Set aside a card from your hand face down. At the beginning of your next turn, reveal the set aside card, then reveal cards from your deck until you reveal a copy of it. Discard the other revealed cards and either trash both copies or put them into your hand.
Interesting. Have no idea how it would play. But also seems like the Duration is very tacked on. Why not simply do the digging now? (And give it +1 action so you can play what you dig for if you keep it).
Vessel
Types: Action Duration
Cost: $4
Now and at the start of your next turn: +1 Buy and +$1.
While this is in play, when another player gains a card costing $4 or more, gain a card costing less than it.
So a sort of Smugglers thing. Except with Smugglers, there's fun in hoping your opponent doesn't have one in hand while you buy your Grand Market / Gold / Goons. Here, you know if your opponent has one, so it more affects your purchasing decision. I guess I like it... but a lot of these cards seem to give +1 buy next turn. Seems tacked on.
Mermaid
Types: Action
Cost: $2
+1 Action. Discard the top card of your deck. Put the bottom card of your deck into your hand. You may put up to 2 cards from your hand on the bottom of your deck.
Why discard the top card? Usually that will do basically nothing. This is a sort-of Haven type thing, except it doesn't increase your hand size later. I dunno, just seems like a weaker Haven. Usually slightly worse than Pearl Diver.
Beacon (B)
Types: Action Duration
Cost: $2
+2 Cards. At the start of your next turn, +1 Card and put a card from your hand on top of your deck.
While this is in play, when you gain a card, trash that card or put it on top of your deck.
Interesting cross between a Moat and a Watchtower. The next turn effect is weird though. Probably should be $3.
Dispatch
Types: Action Duration
Cost: $4
Trash a card from your hand. Gain an Action card costing up to $2 more than it, setting it aside face down. At the start of your next turn, play that Action card.
Again with the setting things aside face down that opponents see you get and put face down. Why? Anyway, this is a pretty simple Remodel variant. The name should be in the Remodel family of names I think. Not all that interesting, but seems fun.
Observatory
Types: Action
Cost: $2
+1 Action. Trash a card from your hand. Look at one card from your deck per $ in its cost. You may put one of them into your hand and discard any number of the others. Put the rest back in any order.
I was about to complain how weak this is compared to Apprentice, then I noticed the cost. Maybe too strong for $2, being a non-terminal Trasher.
Treasure Fleet
Types: Action Duration
Cost: $4
+1 Buy. +$2. When you buy a card this turn, gain a Treasure card costing less than it, setting it aside. At the start of your next turn, +1 Buy and put the set aside card into your hand.
EDIT: Reworded Treasure Fleet so that it only works and is Throne-able.
Problem is, if you are buying a $3 this turn it's terrible. I'm sure there's some way to fix that. And I didn't see the previous wording, but seems this would be better not-throneable, just because by the time you buy a treasure, you have to remember how many times this was played. Other than that, I like it.
Commune
Types: Action Duration
Cost: $2
Now and at the start of every turn this card is in play: Trash a card from your hand. Draw until you have 5 cards in hand.
Do not discard this from play during your Clean-up phase. While this is in play, it is also in the Supply.
This has no reason to be a Duration. It already specifies that it shouldn't be discarded during clean-up. Or alternatively, no need to specify to not discard it; the fact that it's a Duration will do that already. Also why is it also in the Supply? What does that mean? I guess it means I can buy it, and take it from you? Or workshop it and take it from you? But there's also a pile of 9 more of them sitting there... but why would I touch those when I can take yours? Don't like those aspects.
Customs Officer
Types: Action Duration
Cost: $1
+1 Card. +1 Action. While this is in play, when you gain a card, you may return it and this to the Supply. Gain a card with cost exactly equal to the total cost of the returned cards.
So another Duration that stays in play until you use it. I know people will question of this works, because it doesn't have a "next turn" clause.. I *think* it does work as intended, because "while this is in play" means that it's still doing something, therefore doesn't get discarded. I think I like this card. Although... it's this basically a coin token that you purchase for $1? Except with added defense against Curses.
Supply Ship
Types: Action Duration
Cost: $5
Gain an Action or Treasure card costing up to $4 and set it aside. At the start of your next turn, play it.
Generally better than Armory, but probably not better enough to be a $5.
Drift Bottle
Types: Action
Cost: $4
+2 Cards. Choose one: Trash the card on the Drift Bottle mat; or gain the card on the mat and discard a card per $ it costs. Put a card costing between $3 and $6 from the Supply on the mat.
Setup: Put a Silver on the Drift Bottle mat.
Clarification: There is just one communal Drift Bottle mat.
Why the ability to trash? I'm not so sure it should take 2 plays of this to replace the card. Just gain or replace should be ok options. This is more like Rogue / Graverobber I think... trash a card, then gain it. Except the trash is the mat. But still. And you put something great on there, only to have your opponent take it.
Royal Armada
Types: Action Duration
Cost: $5
+1 Card. +1 Action. You may choose an Action card in your hand and set it aside. At the start of your next turn, play it twice.
Ok I suppose.
Raider
Types: Action Attack Duration
Cost: $5
+$2. Each other player discards down to 3 cards in hand. At the start of your next turn, +$1 and each other player discards down to 4 cards in hand.
Do not like attack duration.
Seafarer's Charm
Types: Treasure Reaction
Cost: $0
Worth $1.
When you discard this from play, you may put it on top of your deck. When another player plays an Attack card, you may discard this from your hand. If you do, you are unaffected by that Attack.
Sunken Treasure
Types: Treasure
Cost: $3
Worth $1.
When you shuffle, put this at the bottom of your deck.
Clarification: Seafarer's Charm and Sunken Treasure are not Kingdom Cards. Each player begins with one of each in place of two starting Coppers. Determine whether these Treasures are used by the proportion of Seaside cards, as one would Colonies or Shelters. Sunken Treasure has a special back. When shuffling, you may choose the order in which you resolve multiple Sunken Treasures or Stashes.
Oops, wrote up a whole thing about Seafarer's charm without seeing that it's tied into Sunken Treasure. Yeah, Seafarer's Charm as a Kingdom card did not get good marks from me. Lets see what's actually there.... Ok, still not quite interested. Charm just makes attacks weaker seemingly for no good reason. And Sunken Treasure I guess is a Copper that misses the reshuffles? So?
Side note, just noticed that Sunken Treasure, like Stash, has confusing wording. They make it sound like when you shuffle, you could take one from your hand and put it in your deck. No mention of the fact that you have to be shuffling that particular card to use the ability.
Shipyard (B)
Types: Action Duration
Cost: $5
+2 Cards. Set aside a card from the Supply costing up to $6. While it is set aside, copies of it cost $1 less, but not less than $0. At the start of your next turn or when the game ends: Gain the set aside card.
I don't see a real reason to delay the gaining by a turn, though it does give it a relevant reason to stay out and have the other effect. Of course, the other effect it the same for you and your opponents, so just cancels out in terms of power. Still, it's a $5 cost that can gain $6 costs... Altar is a $6 cost that can gain $5 costs, so I'm guessing this is a bit too strong.
Docks (A)
Types: Action Duration
Cost: $4
Now and at the beginning of your next turn: +1 Card per card you have in play.
Interesting I think.... too strong though? Easy to make this Wharf without the buys, though Villages are needed. Still, makes Villages really, really good. 3 Villages, and playing this is playing a Hunting Grounds. 3 Fishing Villages, and holy crap. Probably ok at $5, but even so these will often be better than Wharf (as long as the game has any form of +Actions and any form of +Buy).
Fishmonger
Types: Action Duration
Cost: $3
+1 Card. +1 Action. +1 Buy. At the start of your next turn, +1 Buy.
Boring... Market Square now, Market Square later, without the reaction. Fine card, but boring.
Scalawag
Types: Action Attack Duration
Cost: $3
Each player may trash a Copper from his hand. If you trashed a Copper, each other player gains a Curse. At the start of your next turn, +1 Card for each Scalawag that any player has in play. If there is more than one in play, trash this.
While this is in play, when another player plays an Attack card, you may discard this. If you do, gain a Silver, putting it on top of your deck.
EDIT: Clarified that it's the Scalawag you may discard when another player plays an Attack card.
Seems strong. The Copper trashing in theory evens out, so basically this is "each other player gains a Curse". You will usually discard it if they play one, so you don't have to trash it (except after the Curses or your Coppers are gone). So I think this is probably pretty much a must-double open. But it's a Duration attack that doesn't have the rules confusion!
Convoy
Types: Action Duration
Cost: $5
+1 Action. Each other player may choose one: he draws a card; or he trashes a card from his hand. Now and at the start of your next turn, +2 Cards and +$1.
Lab now, sorta-Wharf next turn, with opponent benefit to compensate. I have no idea at all if this is balanced, but if it is, I like it. Will make games go quite fast though.
Dock (B)
Types: Action
Cost: $4
+2 Actions. +1 Buy.
While this is in play, when you gain an Action card during your Buy phase, you may put this and the gained card on top of your deck in either order.
EDIT: The under-line effect of Dock (B) is now limited to the Buy phase.
If it's going to be limited to the buy phase anyway, should probably just be "when you buy an action card" instead. Only matters in a couple edge cases. I like this. Maybe it should cost $3, not sure. Doesn't seem stronger than Fishing Village.
Harbour
Types: Action Duration
Cost: $4
+$1. You may trash this.
Do not discard this from play during your Clean-up phase. While this is in play, at the start of your turn, +1 Card. When another player buys a Victory card, discard this from play and gain a Harbour.
Same as Commune with the "do not discard" and "duration" wording.
I don't know how I feel about "every turn" effects in general, but +1 card, and limited to until opponent gains a victory card seem like a good way to do it. But why gain a Harbour when they do? Seems random. And the "you may trash this" only makes sense in light of the fact that you might be gaining extra Habours, so those could both go away. Oh, and +$1 seems random too, since this card is all about extra hand size in future turns; what's the point of giving that particular bonus when you play it?
Shipyard (C)
Types: Action Duration
Cost: $5
+2 Buys. Now and at the start of your next turn: Look through your discard pile, reveal up to 3 Coppers from it, and put them into your hand.
While this is in play, when you would gain a card, you may gain a Copper instead.
Hmm... so an attempt to fix Counting House. I'm thinking this is stronger than Counting House, which is ok. Still won't be viable on most boards, like Counting House, but will be fun when it is, like Counting House. The only concern is if it's too similar to Counting House.
Expedition
Types: Action Duration
Cost: $4
Gain an Action card, putting it on top of your deck. Put a copy of it on the Expedition mat. At the start of your next turn: +1 Action and return the copied card to the Supply.
While this is in play, at the start of each other player's turn, he may play a card from the mat, returning it to the mat from play or from the trash at the end of his turn.
Ultimately this basically seems like a University, except it can gain Goons and Grand Markets, and the Village is delayed. And it gives your opponents a boost to nerf it some. Not sure if the boost is enough to make it not too strong.
Voyage
Types: Action Duration
Cost: $5
Reveal cards from your deck until you reveal 3 costing from $3 to $6. Put those cards on top of your deck in any order and discard the rest. At the start of your next turn, +2 Cards.
When you would discard this from play, instead, trash this and gain a Voyage.
Similar to Cottage, this seems to want to interact with the cards that you left on your deck, but it won't. And why trash one from the Supply each time you play it (which is what the bottom clause does)? I think this is a lot like Journeyman, actually. Or Catacombs, whichever.
Old Seafarer
Types: Action Duration
Cost: $6
Before the Clean-up phase, set aside cards in your play area. At the start of your next turn, discard your hand, put the set-aside cards into your hand, and each other player draws a card.
While this is in play, you may not play an Old Seafarer.
The bottom clause is no good. What if you Golem into 2 of them? Game breaks. It can be fixed by using Crossroads or Tactician type wording though. Also, seems like there's no point to limiting it to one per turn anyway. So basically this replaces your next hand with another copy of this hand. I see why you wanted the clause now... way too strong if you play one each turn. Oh, but the clause won't prevent that. It gets returned to your hand along with the rest of the set-aside cards, so it's not in play. So yeah, this is crazy. It's a King's Court Scheme built into one... you play your same hand every turn.
Settlement
Types: Action Duration
Cost: $5
Now and at the start of every turn this is in play: +2 Buys and +$2.
Do not discard this from play during your Clean-up phase. Instead, discard it from play when any player buys a Victory card.
Same as Commune/Harbour, no need to say "do not discard this". The fact that it's a Duration will do that. Or vice-versa. And it has the same discarding condition as Harbour, interesting. Anyway, seems strong. Very strong. Better than Grand Market every turn. Will force opponents to buy Estates and Duchies just to stop it. But they do have the ability to do that. So ultimately, I think this will act as a junking attack. It's so good that your opponent will buy crap to make you not have it for another shuffle. I think if you also make it discard when you buy a victory card, that would be good. Probably should be $6, might be a good card.
Coastal Raiders
Types: Action Attack Duration
Cost: $3
Each other player discards down to 3 cards in hand. At the start of your next turn, +$3.
Probably can cost $4; doesn't seem much worse than Militia. Not too exciting, but fine.
Sea Harvest
Types: Action Duration
Cost: $5
+1 Action. Gain an Action card costing less than $1 per card in your hand. At the start of your next turn, gain a Treasure card costing less than $1 per card in your hand.
So next turn will almost always be less than $5; except with Wharf/Caravan and discard attacks. Might be too strong. Sure KC-KC ANYTHING is a crazy effect, but KC-KC Draw-Sea Harvest-Sea Harvest means you gain 6 more KCs. But there's plenty of other ways to use this to gain KC and Goons and GM, non-terminally no less. I like the mechanic that each one you play is slightly weaker than the last, but still.
Shipyard (D)
Types: Action Duration
Cost: $5
+2 Cards. Put a card from your hand on top of your deck. At the start of your next turn, gain a card costing up to $4, putting it into your hand.
I dunno. Workshop variant... but a strong one. Though the 2 effects seem to be completely unrelated. I guess I like it ok.
There... thanks a lot people, now I have several hours of lost time to make up for at work!