Alright, let's do this. Sorry for the delay, I tried to give a good writeup on as many cards as I could.
(Slight wording and syntax tweaks have been done to a couple of these cards. They shouldn't change what the card was going for. If it did, apologies. I tried to interpret these the best I could.)
czzzz - Chef (Action, $5)
Trash a card from your hand to gain a card to your hand costing exactly $1 more than it. If you didn't gain a card this way, +3 Cards.
Pretty versatile for a Smithy variant. Immediate comparison that comes to my mind is actually Sacrifice vs. Moneylender. They both cost the same, but Sacrifice gives you 1 less coin for the ability to trash more things and some nice benefits for doing so. Likewise, the Upgrade/Transmogrify effect tacked on to cards you're gonna gain with this more than makes up for the 1 less card you get for trashing a Copper (not to mention not having to deal with Cursed Gold). Works well. Not flashy but doesn't need to be.
majiponi - Almsgiving (Action, $2)
Discard a card from your hand to choose one: +3 Cards; +3 Actions; +3 Buys; or +$3.
A card that works in threes... that costs $2. Incredibly minor thematic nitpick aside, seems to have the Nobles effect of being solid enough, but something you wanna slip one or two copies just to round out things well. I think this fills that role better than Nobles, albeit with no VP attached. You could discard-first sift with three copies of this if you're desperate, but using three $2s to sift three cards feels a bit cumbersome. My only complaint is that this could play slowly if someone were to do something similar to mass Forum, but I see this card getting better use than that.
grep - Elixir (Action, $4)
Choose one: Take the -1 Card token for +$3; or take the -$1 token for +3 Cards.
...Too weak for a $4 cost. Given that you're essentially going to be playing alternating +Cards and +Coins with this (since you can't get benefits if you already have the respective Token) this would be a quality if slightly weak 2-cost. Good ideas, I think this just suffers from pricing.
NoMoreFun - Courses (Action, $4)
You may discard a card for +2 Cards. You may discard 3 cards for +4 Cards. You may discard your hand for +6 Cards.
Sifting a bit for cards in cycles. Very thematic in getting as much as you want but probably suffering a bit from taking too much. I'm a bit conflicted on whether to price this at $3 or $4, but since it's without sifting either a +2 Cards or draw-to-6, I'd lean towards $3.
xyz123 - Renovate (Action - Duration, 8D)
Trash a card from your hand. Gain a card costing up to $2 more than it onto your deck. Either now or at the start of your next turn, +1 Card and +1 Action.
Remodel-to-hand effects are pretty rare, and I don't think there's any currently in the game that remodels by 2 while putting it somewhere. I like the now-or-later part of choosing whether to take the card now or next turn, but any form of draw after playing this means you don't really have a choice. Still, probably nice to start next turn with an extra Action. Not sure what to think of the debt cost, but I think it works.
JW - Covetous Witch (Action - Duration - Attack, $6)
You may discard a Duchy or Gold. If you did, each other player gains a Curse.
At the start of your next turn, +4 Cards.
Immediate comparisons to Legionary come to mind. Big bonus, plus a requirement for another card in hand to pull out the Attack. Not much else to say here, just a nice card all around.
AJL828 - Craftsman (Action - Liaison, $4)
Gain a card costing up to $4. +1 Favor per $ less than $4 it costs.
...It's a Workshop variant. Good card, I can't complain about it, but there's not much here to complain about.
kru5h - Builder (Action, $6)
Gain a card costing less than this. If it costs $4 or less, +1 Card and +1 Action.
Another Workshop variant, but I can actually talk about this one a bit more. It's nice being able to choose between gain $5 or cantrip, and I see myself doing both during the course of a single game. One of the few "gain costing less" cards that actually kinda likes cost reduction. Nice work!
4est - Swamp Village (Action, $4)
Play up to 2 Actions or Treasures from your hand. Discard your hand. +4 Cards.
One of the most fun Lost City variants I think I've seen yet. You're going all in on this. Traditional draw straight up doesn't work anymore. It plays like Draw-to-X where it's situationally very powerful, but you're restricted by choosing not to put certain cards in your deck. Seems very enjoyable, and I'd love to see this in an actual expansion.
BryGuy - Wise Jester (Action, $5)
Choose one: set this aside for +1 Card, +1 Action, and either +$1 or +1 Buy (discard during Clean-up);
or trash this for +4 Cards and either +1 Action or +1 Buy.
I really should've disqualified this because I see no point in setting this aside other than to stop it from being Throne Roomed. Oh well, too late for that I guess. It's choose between Peddler, Market Square, or dump it for a bunch of cards. I saw this get revised like four times in the thread here, and that's pretty apparent in how it seems to play. Probably should just get scrapped. Sorry to say that, I know you put a ton of work in trying to get this to work, but it just doesn't.
faust - Water Wheel (Action, $4)
This turn, after you play a card, discard a card for +1 Card.
As much as I like this card in concept, this seems hella annoying to play with or against. Especially online. Having to go through two extra clicks for every single card you'd play is gonna slow each of your turns down dramatically, especially if you open this for consistent $4s or to get $5 with this-Silver. I want to like this card so bad, but I can't.
SignError - Tithe Collector (Action - Attack, $4)
Each player with 5 or more cards in hand trashes a Treasure from it (or reveals they can’t). If anyone trashed a Copper this turn, +$3.
Inverse Moneylender! Genuinely surprised no one's thought of this before, but maybe that's because there's so many different ways you can attack in this game. Nothing more to say here, just a nice unique Attack.
X-tra - Lake Creature (Action - Duration - Attack, $5)
Each other player with no cards in their discard pile discards down to 3 cards in hand. If they didn't discard cards this way, they gain a Curse.
At the start of your next turn: +2 Cards.
Solid attack. I'm not sure how the "no cards in their discard pile" line is going to work in most games, but this occasionally Militia-ing instead of Cursing seems enough to warrant this being its own thing. I wanna see how it plays, because I genuinely have no idea how frequently the discard attack is going to trigger. Don't buy this in a Swashbuckler game.
sumrex - Gate Guardian (Action, $3 2D)
Exile two non-Victory cards from your hand, then if their combined cost in $ was:
0: Gain a Copper;
1-4: +1 Buy, +$1;
5 or more: +$3, +2 Buys.
Per Potion in the cost of Exiled cards, gain a card costing up to $5.
I understand the intention behind this card is to try and Exile cards you no longer have use for for coins, but... I don't understand what I'm supposed to be Exiling with this? Due to the non-Victory card restriction, Copper's gonna be the primary thing to Exile here, but after that... what do you Exile? Other Gate Guardians? Lackeys? Stonemasons? You're not going to have cards that 1) cost at least 1 coin, 2) aren't victory cards, and 3) that you want to buy, but don't want to keep out of Exile on most boards. I think this card is unique, sure, but it doesn't pass the Silver test for me, and that's unfortunate because I see potential here. I'd honestly get rid of the non-Victory card restriction. Sure, that'd probably make it better than Bounty Hunter, but it costs more, so I think you could get away with it.
silverspawn - Foundry (Action, $4)
Reveal your hand. For each Action or Treasure with more than one copy revealed, discard one copy.
+4 Cards
Hunting Grounds, but all your non-uniques get hunted prior. This is honestly a card that could use that name more. Having to build your deck around not having uniques for that extra card sounds like a fun challenge on a good amount of boards. Very good card, not much else to say.
LTaco - Jury-Rigging (Action - Duration, $4)
Now and at the start of your next turn: Reveal the top card of your deck; discard it or put it back. +1 Card per type it has.
Finicky kinda-Caravan. Gives two types on its own, but you're frequently only going to see one in the majority of cards (compare Maroon with less choice on what card you pull). At the very least, this is like Catacombs where you get to look at the cards you would draw before choosing whether or not to take them. Very nice card, and one of the ones I think I wanna play with the most of all them here.
Honorable Mentions - Builder, Chef, Courses, Lake Creature, Renovate, Tithe Collector
Runner-Ups - Foundry (silverspawn), Jury-Rigging (LTaco)
Winner - Swamp Village (4est)
Thanks for all the great cards, everyone! Loved hosting this, and I can't wait to see what cards you'll bring to the next contest!