And now, my thoughts on the submissions. I've organized cards alphabetically.
Collector (by Fragasnap): I like that it kind of works against itself, but I feel that this will be too obvious a buy in TfB engines, since this is super good if you can use the Gold.
Compass (by Chappy7): Combining a trasher with Lost in the Woods seems... odd? LitW is best in slogs when you don't mind discarding for a random benefit, and this trashes and then gives you LitW when you are already thin enough to want to get rid of your trasher... I can't imagine it will do much at that point.
Gatekeeper (by Holunder9): Holunder9 is banned and thus excluded from this contest. I will still share my thoughts on this one. I think it is an interesting way of making a "2-shot" card. I wish it didn't use Coffers and just gave a standard +3$ though.
Pioneer Village (by King Leon): I just don't think it is a good idea to try and use orn and Lantern for some other card. Also Lantern/Horn gaining is supposed to compensate you for having to discard a good card, here you get it when you reached the best-case scenario for the card anyway, which I don't like.
Revenant (by spiralstaircase): This is... quite weak? As a Remodeler, it is quite slow, and you have trouble connecting it with the right card. The "exactly $3" requirement means it doesn't even work with Gold gainers. As an attack, the worst it will do is giving your opponent -4VP, which basically amounts to playing a Distant Lands.
Rival City (by NoMoreFun): It seems like a very bad idea to get the Flag with this around, and without the Flag it's just a pretty bad Village. Of course you can use it as a way to get the Treasure Chest/Key, but that just doesn't seem terribly interesting.
Scrooge (by Asper): I like the simplicity of it, while at the same time being quite thematic. It's an interesting late-game card for an engine thanks to the +buy. This bonus also helps making sure that this isn't too good a BM card. I like it.
Spendthrift (by Commodore Chuckles): I don't think being able to take the Treasure Chest makes up for being terminal. I like that Envious is combined with the Treasure Chest, but find this a bit too weak.
Tinkerer (by Gubump): I don't think I like the concept of slapping even more benefits onto an Artifact. This card is quite swingy and on top of that I don't fully get the thematic link to the Key.
Vanguard (by hypercube): The design is very neat, though I suspect the card could be quite dominating. And in the end I think I would prefer a design that doesn't need to be labeled an attack since that creates rules confusion with whether you can take the Flag from someone blocking the attack.
Voyager (by scott_pilgrim): This is novel and interesting. I think it is a bit too much though on a draw card that will often be played multiple times on the same turn; the "bidding" should only happen once per turn.
Winner: Asper with Scrooge. Runner-up: scott_pilgrim with Voyager.