Thank you all for bearing with me. This challenge had the problem that it was almost a puzzle, as it was very easy for ideas to become overly complex, or for them to use components in a non-meaningful way. So kudos to everybody who still made an effort to submit a streamlined, elegant card under these conditions. I hope I didn't forget anything:
Godfather: I like how the card manages for Copper, Silver and Gold to be worth exactly their amounts with the new wording. Nice! It does look a bit too strong, though. Perhaps using just coins instead of Coffers would have worked? I would have suggested to drop the Boons, but I guess my "great" challenge rules ruled out Coffers. I very much enjoy how the theme plays into this, by the way.
Trade War: One of the sleekest and most elegant submissions. It might be a bit strong, but on the other hand you'll see your new cards less often, and enough people complain about Treasures anyhow. Very neat.
Cannon: I am almost sure this is a Gunpowder joke. It doesn't really feel like it needs or wants a Potion cost, to be honest.
Mosquito: This has a lot going on. +3 Cards, put an Embargo Token on a supply pile, take you -1$ token, -3 VP. I realize I made it hard with this challenge (sorry), but I think this could lose one or more of these things. I do think there's room for interesting ideas here, though. Sadly, this also seems very weak.
Silk Farmer: A nonterminal trasher that replaces the other cards with a Spoils or can be cracked up for two Spoils... Similar to both Altar and Pillage to some degree. I like that, and I like that the Night type is used in a meaningful way.
Hill Tribe: I like this more than your original submission, but while I love how sleek this is, I'm unsure how often you will want to actually delay those Spoils. I mean, you just paid a card, do you want to pay another one to use it later (you'll have to draw it again)? Maybe the decision would be more meaningful if you just gained the Spoils and then could take your token to put it in hand?
Bewitched Town: Well, apparently I'm doing that all, after all

I do like the idea of mixing Villagers with Potions, but I don't feel this needs Ill-Gotten-Gains to be on it. Re-filling the supply avoids an IGG rush, but the Potion price already does this. And on its own, this card wouldn't run out of Curses, anyhow.
Amphitheatre: Another one that I like for how clean it is. I also really like how this plays both into the Actor and Antiquity theme. Cute! However, even if this only topdecked one card, making it topdeck itself still basically means a free +1 Action for each of your following turns, with Actions you don't need staying around. In that respect, making it topdeck just two cards seems fair already - also with two Villagers and two cards topdecked, I think the symmetry would be sweet. Admittedly, I didn't give this much consideration before looking at it closer. Nice one!
Bacchanal: Another one that combines Antique with another theme. Also sweet. The debt cost makes sense to keep you from gaining copies of itself, although of course you could have said "that is not a Bacchanal" - but it does also feel like the cost belongs on it. Like other expensive debt cards, it's also not as good early on. I'm not 100% sure it needs the Villagers thing, but it's not like it's too much text there, anyhow. Nice.
Homestead: Okay, so maybe my challange wasn't all garbage. So many nice cards here. Overpay for Villagers is a really cute and simple idea. This seems like a card you could see in regular Dominion. Only downside is that there already are two "on-gain" Villager cards in Renaissance - but of course both of them are also terminal draw (which is kinda weird, to be honest).
Leper Colony: Hum, I think this would need you to look through your deck. I guess this would eat up your Coppers really quickly, so it might be stronger than one would think at first. However, with Victory cards being excluded, I'm not sure this is all that different from just trashing the cards. Sure, there are curses and things like Gardens sometimes, but often there aren't. I do like the theme, even though it's a bit... morbid.
Crocodile: I like how the Night type here prevents you from being affected yourself, and just costing every card 1 debt more solves the issue of excluding people from the game. And Crocodiles are nocturnal aquatic animals, so that's also neat. I don't exactly enjoy the fact that the card isn't an attack, and would have suggested to implement such a thing with a Swamp-Hag-like wording instead... As a matter of fact, I did. Also, the on-play bonus is not very good. Unless you have excess buys (which this card doesn't create), you'll often be able to pay 4$ anyway, and even if you don't, you'd need to have a second Crocodile in hand when you buy this to actually remove debt before your next buy phase. Apart from that, the only way to get debt is for other players to play the Crocodile game. I do like a lot about this, but some parts seem like they could be improved.
Exile: Like Leper Colony, this sends the outcasts to an Island. Nice. This probably wants to cost 4$, though. Opening with two of these leaves you with a gret deck and lots of tokens in no time. That seems a bit automatic, to be honest. Especially as you don't necessarily need to build a real deck from that state on (unlike with Chapel), as you can Island away your Victory cards.
Shaman: I agree that this could be shortened quite a bit. "You may trash a card you have in play. If it is...". I agree that the Action choice would need to be stronger to be worth it.
Underground Railroad: This doesn't really seem worth it. Sure, you can ideally put your hand on your mat, and if you are lucky, the Victory cards stay there. But you have to get rid of at least three cards at once to make it even possible r this to turn out worthwile (unless you were unlucky before). You might have lots of cards you want to lose in hand if you draw your deck, but then your engine already is running smoothly, so this is just making you win when you already win. If I hadn't excluded Events (my bad), I probably would have suggested to do it that way, instead. It has a unique twist to it, but I can't really imagine how this should be played for good use.
Golden Egg: Yes, this is technically not following Donald's guidelines for overpay (he wanted benefits to always scale with the amount paid), but well, Donald isn't here... I do admit that I'm not a very fervid Villa lover, so the "return to your Action phase" doesn't excite me all that much. I guess being able to overpay to turn your Journey Token over is fine, but I'm afraid other cards that have been submitted convince me more.
Ossuary/Cursed Skull: I like this thematically, and I appreciate that it cuts down on the 1st player advantage. It might be a bit much to spoil somebody's 5/2 opening, though... Apart from that, I certainly like the +VP version more. Again, it might be a bit too harsh. Maybe there could be bonuses where you can hold onto your current turn at the expense of a future one, as in taking debt for buying cards or something. I do like the idea to combine Landmark and Artifact.
Woodland Path: A sweet replacement for Fool that actually is easier to set up. It might still be a bit slow to resolve, though. Imagine the same decision for every player, every turn, looking through the discards. But what am I saying, this is still much better than an official card, so congrats to you.
Winner: Dsell's Bacchanal
Runner-up: Commodore Chuckles' Homestead