Dagger - A very nice $2 cost. I'm curious how fast this can trash with perfect draws (every turn?) and how that would compare to the worst draws possible. Are the these two scenarios so far apart that it warrants concern? Probably not as luck will always be a part of Dominion. You probably don't want it every turns anyways to avoid terminal collisions.
I changed Dagger to this:
Dagger Action - Treasure,
If it's your Action phase, trash a card from your hand.
If it's your Buy phase, +1 Buy.
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When you discard this from play, you may shuffle it into your deck.
I wanted a 1-cost in my cards so that it combos with Cooper.
King Midas - Another very cool concept, but this one has the potential of being very swingy. The top part seems fine, but the bottom part has the potential to trash Provinces with no real way of playing around it. Maybe make the trashed card come from your hand and cost between $3 and $6 coin? This seems like a Duchy rush kind of card, so losing even one of those would hurt a lot. I also feel this could cost $5 and be fine. Blocking Province buys is a delicate balance and you probably want to make them a little less accessible.
Yeah, too swingy. I'm not going to keep it.
Bon Vivant - Seems a bit powerful. Kind of eliminates a whole subset of Dominion cards that give reliability in your deck. I really like the idea, but would find this much more exciting if the decision were a little harder to make. Like play the Action or take +2 Actions/+3Actions (without the +1 Card). In addition I feel Bon Vivant itself should not give extra Actions. It could probably just be a cantrip and cost $2 with both of those changes.
It's really hard to give interesting options to Villages. Either you need a village or you don't, so either you take the village option or you take something else entirely dependent upon the situation and not any long-term considerations. I think this might be a little strong, but it's not as powerful as it seems: If you overterminal your deck, you will never draw the Bon Vivant you need to get your train going. It basically turns other cards into a 3-cost card, which isn't amazing. I'll keep it how it is for now but think on it some more.
I could do this:
Bon Vivant Action,
+1 Card
+2 Actions
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While this is in play, when you play an Action card, you may get +2 Cards instead of following its instructions.
But that's just really similar to Asper's "Road" at that point. (Although, it can't go infinite.)
Judge - I can't say much in terms of this being balanced or not, but boy does it seems cool. $6 might be a fair starting point as this seems it will likely just be a Duchy or alt-VP gainer. I really like the oversaturation mechanic. Having 10 of these will likely only result in maybe 4 to 6 of those turns being worthwhile as Judges are put back into your deck after each extra turn.
I'm still thinking on Judge. I don't like Tavern mats because my set is supposed to be an Intrigue sequel, but I'll think about it some more. The most annoying thing about this is that the extra turns could be obnoxious, so I'm going to turn it into a split pile. That does two things: Reduces the number of them, and I can pair it with an interesting Victory card so that there's something to go for besides Duchies after the provinces are gone. Something like this:
Judge/Courthouse Victory Split Pile (Supply 12)
This pile starts the game with 6 copies of Judge on top, then 6 copies of Courthouse.
For a 2-player game, use only 4 of each card. Only the top card of the pile can be gained or bought.
Judge Action - Reserve,
Put this on your Tavern mat.
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When the game ends, you may call one Judge to take an extra turn after this one in which you cannot play Judges. Resolve multiple Judge calls in turn order, starting with the next player.
Courthouse Victory,
6
You get extra turns, but your penalty is that the "Provinces" (Courthouses) cost 10 now.