This is a lot, so I'll confine my comments to the ones that stand out to me.
Pub
Cost: 2
Action
+1 Coin
+2 Buys
When you want lots of Buys (e.g., Gardens, Goons, Vineyard, Silk Road)
and can't get them any better ways (Worker's Village, Market, maybe Pawn) this is pretty great. But those boards are going to be few and far between. Extra buys often go wasted, and this probably just means
more buys go wasted -- particularly since it only gives you $1 extra to spend with them. I'm not opposed to a +2 Buys card, but I really think it needs to be on a card that synergizes with fat decks and/or high money hands in some additional way.
Telescope
Cost: 2
Action – Duration
+1 Card
+1 Action
At the start of your next turn, you may discard your hand, if you do +4 Cards
I like this one, but I wonder about its cost. The other $2 cantrips include: (1) Pearl Diver, notoriously weak; (2) Pawn, which doesn't do anything else if you use it as a cantrip.
The thing is, it's probably fine for $2 in terms of power level, but at the $2 price tier it's probably more important to look at how the game will play if people have extra buys and a few coins to burn on them. In that event, this pile will go fast -- not because anybody actually wants Telescopes but because, hey, why not pick up some with spare cash? At $3, this won't happen quite as frequently (while still being a pile that's easy to deplete for a 3-pile ending).
As far as the function of the card itself is concerned, I like this variation on Navigator. Whereas Navigator can be used in combos to pick the cards for a subsequent draw, this one also makes a nice counter to discard attacks...my point being that although they're very similar, they have their own unique niche.
Colonist
Cost: 3
Action
+1 Coin
+1 Buy
Gain either a Silver or an Estate on top of your deck
I don't get this one. What does a Colonist strategy look like? A single Colonist in a Big Money deck is the only non-destructive use I can think of, and there are plenty of more interesting X's for BM+X. If you have an engine, the Silver will gum it up. If you don't, you have to pick your terminals sparingly, and this one won't look very good on most boards.
It would be different if this card did something others don't. Herbalist is a pretty weak card, but when you want its treasure-return feature, you need Herbalist. But Bureaucrat and Jack of All Trades will get you Silver, and in different ways so will Trader and Haggler and Talisman and Horn of Plenty and simply buying Silver outright. The Estate option will basically never be used unless its the last turn of the game.
Diplomat
Cost: 3
Action – Attack – Reaction
Gain a Silver
All opponents gain two copper
- - - - - - -
You may reveal and discard this card to remain unaffected by an opponent’s attack card
This is brutally strong, I think. Junking attacks are among the most powerful in the game, and the ability to sabotage someone else's deck while improving your own basically forces your opponents into a mirror match. Then again, the fact that you're gaining Silver will slow down your ability to play these a lot, so at least it's self-correcting in that sense. I'd probably cost this at $4.
My other reservation is purely personal: I'm not fond of games that force you into Big Money strategies (actions are so much more interesting), and this card basically forces everybody into one. If either you or your opponents try an engine with this card in play, it'll get junked up by this card.
Factory Town
Cost: 3
Action
+1 Card
You may trash a card from your hand, if you do +2 Actions
Too strong, I think. If you open double Factory Town, trash down, trash one of your Factory Towns with the other, then treat the remaining Factory Town as a dead card -- never playing it at all -- then that's probably reason enough to price it at $4. Non-terminal trashing is really really good, and all the more so if it helps you replenish your hand a bit as well (replacing itself in your hand, though not the trashed card).
School
Cost: 3
Action
+1 Action
Gain up to two action cards costing up to 3 placing them in your hand
Others already pointed out the logistical problem with this, which is that 3-pile endings can happen pretty much instantly: drain this pile on turn 3, then drain 2 other piles with all your Schools at your leisure. It may not be a great strategy a lot of the time, but with Great Halls on the board, probably whichever player gets to play School first wins.
Gaining action cards to hand is rife with subtle little problems like these, which is probably why Donald has (to date) thrown out all the Remodel variants he's tested that did that.
Field Nurse
Cost: 4
Action - Reaction
+1 Card
+1 Action
+1 Buy
Trash any number of curses from your hand. Gain a card costing equal or less than the number of curses trashed
- - - - - - -
When a card is trashed from your deck, discard pile, hand or play area, reveal this card to put the trashed card in your hand instead
The reaction part is insane. Combo this with any trash-for-benefit (Salvager, Bishop, Remodel, Apprentice, etc) and you can't run amok. The action part is almost worth $4 all by itself, though not quite, because you're probably never going to want this as a Curse trasher. Why? Because most of the time all you can do is trade them in for Coppers. If you manage to draw this with enough Curses to get something useful back, you've already lost.
Gong Farmer
Cost: 4
Action
+1 Card
+1 Action
If there are no cards in the trash, +1VP
You may gain a card from the trash into your hand
- - - - - - - - - -
When you gain this shuffle all the cards in the trash and reveal the top card and choose whether you gain a copy of the card or all opponents do
In a great many games, this is simply an infinite-VP card. It'll easy lead to broken game states, where the optimal strategy is not to do anything but play a bunch of these each turn. I'm convinced it's impossible to make an interesting trash-picking card (though there was a thread here a while back where someone got a lot closer than I would have thought possible), but the trash-picking part isn't the main problem here. Best to leave the trash in the trash, and avoid non-terminal VP chip earners too.
Tavern
Cost: 4
Action
+1 Coin
+2 Buys
For every unused buy this turn, +1 Card during the clean up phase when drawing your hand for next turn
I mentioned that Pub was too weak/situational at $2, but this, the same card but with the last line added, is too strong for the exact same reason that Pub was too weak: Providing 2 extra buys but only 1 extra coin is going to mean that the extra buys go wasted most of the time. What's probably going to happen with this is that someone playing Tavern winds up with, I dunno, $3 to $9 to spend, buys one card, doesn't even WANT to use the extra buys and now ESPECIALLY doesn't want to waste them, because each one is a free Laboratory next turn. So at minimum that's two Laboratories next turn, for just $4.
It's possible that the fact that this is only a terminal Copper
this turn will make up for the power boost next turn, but that's a heck of a power boost all the same.
Unions
Cost: 4
Action - Attack
+2 Coins
All other players with five or more cards in their hands must discard a treasure card or reveal a hand with no treasures
A Cutpurse most of the time, but trades being able to hit Silvers and Golds sometimes with not being stackable. This is probably fine.
Villa
Cost: 4
Action
+2 Actions
+1 Coin
+1 Buy
Almost certainly too weak. Although it's only one coin off from being a Festival, that actually makes it a whole lot weaker. (Note the price difference between Copper and Silver.) I'd probably want to price this at $2, frankly. It's a touch strong there, maybe, but a touch weak at $3 (losing Fishing Village's coin and action next turn for only a buy this turn).
Refrigerated Goods
Cost: 5
Action
+1 Action
You may play Victory Cards from your hand. +1 Coin for each victory card played in this manner.
Best just to have the Victory cards discarded, rather than played. Otherwise you'll get into rules hang-ups with Action-Victory hybrids.
This is probably too weak, too, although potentially strong with a large hand size. But compare to Secret Chamber. Adding +1 Action possibly compensates for losing the reaction part and only being able to use this on Victory cards, but there isn't a $3 price hike in there at all. It anti-synergizes a bit, too, since to get the most out of it, you need to discard a lot of cards, and if you're able to do that, you're not as likely to need the +1 Action in the first place.
During the mid-game, this is probably a purely dead card; in the late game, you're lucky if you get better than a terminal Silver out of it. Compare with Baron: you only need to collide it with one Victory card (admittedly, it has to be an Estate), but when you do you get +$4 out of it. And a +Buy, whether you do or not. And Baron is cheaper.
Revolution
Cost: 5
Action – Attack
All players (including you) reveal and thrash the top card of their deck. All players (including you) may then gain a card whose cost is two less than the card they thrashed or a card that costs zero.
So, Saboteur that hits you too? No thanks! If it happens to every player, why would I ever buy this? How could I ever secure an advantage from it? If I even wanted to have this effect (and why would I?) I'm better off if someone else gets one instead of me. Then they can waste the buy on getting one, and the card slot and action on playing one.
Steam Engine
Cost: 5
Action
+2 Cards
+3 Actions
While this card is in play, gain a curse whenever you buy a non-action card
Only ever buy Steam Engines and money-earning terminals, then buy out the Provinces for a mega-turn. The curses won't matter.
Machine Gun
Cost: 6
Action - Reaction
+1 Buy
Trash as many cards as you like. +1 Coin for each card trashed in this manner
- - - - - - - - - - -
You may reveal this from your hand to gain cards from opponents attacks into your hand instead of their usual locations
The reaction part is problematic. What's a "card from opponents attack"? I assume you mean, for example, a Curse from a Witch, but it's not necessarily always clear where a card is coming from. Technically it doesn't come from the attack anyway. It comes from the supply. And if a Curse, which you gained because your opponent played a Witch, counts, how about the Silver you gain instead because you first revealed Trader? Also, how about this hypothetical card:
Witch Embassy
$4 - Action/Attack
+2 Cards
Each other player gains a curse.
--
When you gain this, each other player gains a Silver.
Does the Silver you get when your opponent buys a Witch Embassy count? What if your opponent ambassadors you a Cache? Do you get to reveal this card on the Cache only, or also on the two Coppers that come with it?
Reaction triggers are complicated enough -- witness the many long and confusing threads about it in the Rules forum -- that it's best just to stick with simple triggers. This probably suffices: "When you gain a card during another player's turn, you may reveal this from your hand. If you do, put that card in your hand."
Standardised Goods
Cost: 6
Action
+1 Action
+1 Coin
+1 Buy
Reveal your hand. Reveal cards from your deck until a revealed card shares a name with a card in your hand. Put the matching card in your hand discarding all other revealed cards
- - - - - - -
While this card is in play, when you buy an action card, you may choose to gain an additional copy of the card bought.
This is almost certainly broken. Basically the action portion is a Market where the card you draw is not necessarily the top card of your deck, right? It's fairly common, when Market is in play, to have multiple Markets played per turn. And when you have the "while this is in play" clause, it will be more common, because you're going to want to try to play as many of these as you can. It won't be long before people are getting 5 Festivals one turn, 5 Conspirators next turn, and so on. Plus, it feeds off itself. So you buy one of these at first, and maybe next time it comes up, you buy 2, and so on. Grand Market is already like that (having some means being able to buy a larger number later), but the race is constrained by the no-Copper clause and -- more to the point -- the fact that you have to be able to afford each copy of it you get each turn.
With this, well, if you buy a $6 card, then this card gives you an extra +$6. That's pretty wild.
Contrast with how other cards allowing you to gain action cards are limited:
1. Talisman: $4 is the price cap, and most of the power actions cost $5+.
2. Haggler: Terminal action, so it's hard to play multiples, and only gets you a card costing less than the purchased card.
3. Border Village: Offset by the fact that you're playing $6 for a Village.
4. Horn of Plenty: Have to work to construct a deck that can play enough cards to make this gain the power cards.
Here, you have (1) no cost cap, (2) a non-terminal that's easy to stack, (3) semi-decent if slightly overpriced value even without the card-gaining clause; and (4) no tricky deck-building required to get it to fire.
World Fair
Cost: 6
Action – Victory
+2 Cards
+2 Actions
+2 Buys
You may only play one World Fair a turn
- - - - - - - -
2 VP
If Golem turns up two copies of World Fair, which rule to you break? Golem's or World Fair's? Better to say "If this is the first time you've played a World Fair this turn..." and qualify that way.
Even so, this is STILL a must-buy card every time it's on the table. Maybe you buy extras and maybe not, but that first copy IS a must-buy. That means the card narrows the strategy space of the game, rather than opening it up by providing additional options. So I'm not a fan of the card on that basis. If you want to pack power into a card, it's much better to make it conditional on the right circumstances (Horn of Plenty can gain Provinces, Secret Chamber can give you +$15) or with a drawback (Tactician requires you to discard this turn's hand, Bishop lets other players trash for free) rather than simply limiting how many times you can reap the full effect.
Barracks
Cost: 7
Action - Victory
+3 Cards
+1 Coin
+1 Buy
- - - - - - - - -
1 VP for every two attack cards in your deck
- - - - - - - - -
When you gain this, each opponent gains a copper
Just the vanilla bonuses are worth $7. Adding the other stuff makes the card quite a bit more powerful. I'd also say that the "worth 1 VP for every two attack cards" bit is problematic simply because it's often going to appear on boards without any attack cards. But since that part is gravy on top of what is already strong enough, it's not as big of a deal. But I really think you're overestimating how strong a $7 card can be.
Have you playtested any of these cards? My guess is no -- I think if you did, even in a solitaire game you play with yourself just to see how they work, you'd be surprised at the power levels of several of these.