My comments on a few cards:
Dancer
Types: Action
Cost: $4
+1 Card. Take a Coin token. You may pay any number of Coin tokens. For each token you paid, +1 Action.
When you gain this, take a Coin token.
I like it at $3 cost. Wouldn't work well as an only village in an engine, but I think it'd work great in a BM+ deck or with other village cards where you could use it as a village sometimes or use it to collect coin tokens other times. I don't think it's supposed to be used as a cantrip most of the time.
Royal Guard
Types: Action – Reaction
Cost: $3
+1 Action. Choose one: Take a Coin token; or pay any number of Coin tokens and +$2 per token paid.
When any player (including you) plays an Attack card, you may discard this from your hand. If you do, take 2 Coin tokens.
I think like it. But I think it'd be underpowered if there were no attack cards or other coin token cards in the kingdom, and it'd be hard to strengthen it without making it overpowered with attack cards.
Councilman
Types: Action – Attack
Cost: $8–
+1 Card. +1 Action. Each other player pays a Coin token. If nobody did, +1 Card and +1 Buy.
You may underpay for this card. For each $1 you underpaid, each other player takes a Coin token.
I like the idea (including the underpay), but I don't think it works well as-is because of what eHalcyon said. Also, I'm not sure if it means each other player gives you a coin token or returns a coin token to the suppy. I'd like it better if they give you the coin tokens.
Jeweler
Types: Action
Cost: $3+
Take a Coin token. Name a card. Each other player reveals his hand. If the named card is reveald, take a Coin token.
When you buy this, you may overpay for it. Take a Coin token per $2 you overpaid (rounded down).
I think overpay for coin tokens might work if it's 2 for 1 like this, but I don't like the top.
Pawnbroker
Types: Action
Cost: $3+
Take a Coin token. You may trash a card from your hand. If you do, take a Coin token per $2 in its cost, rounded down.
When you buy this, you may overpay for it. If you do, the player to your left chooses a card in the Supply costing exactly $2 more than the amount you overpaid. Gain it.
I kinda like the top. As for the overpay effect, I don't like the idea of someone else choosing the card you gain, but then it would work nicely if you paid $9 for the pawnbroker (as long as there's no peddlers).
Porter
Types: Action
Cost: $2+
+1 Card. +1 Action. You may put any number of cards from your hand on top of your deck.
When you buy this, you may overpay for it. For each $1 you overpaid, set aside the top card of your deck, putting it into your hand at the start of your next turn.
The top seems a little weak, and the overpay effect seems a little overpowered. Maybe it balances out. I'm inclined to like it, but I want to playtest it to see how well it works. I'll vote for it in the first round anyway.
Tiller
Types: Action
Cost: $4
+1 Action. Reveal the top card of your deck. You may pay a Coin token. If you do, put the card into yoru hand. Otherwise discard it and take a Coin token.
As-is, I might be good at $2. But I would suggest removing the 'pay a coin token' part and just say "You may put the card into your hand. Otherwise discard it and take a coin token." Then I'd like it better and it might be good at $3.
Demagogue
Types: Action
Cost: $4+
You may discard a Treasure. If you do, +2 Cards and +2 Actions.
When you buy this, you may overpay for it. Each other player reveals 2 cards from his deck per $1 you overpaid, puts the revealed Coppers back, and discards the rest.
I think the overpay effect would work better either on a cheaper card or as part of the top (probably revealing 3 cards). Also, I think it'd work better if the attack was "discard all revealed cards costing more than $2 and put the rest back. I'd suggest moving the attack to the top and making it cost $5. Of course then it doesn't fit well in guilds, but I think it'd be a better card.
Bookkeeper
Types: Action
Cost: $3
+1 Card. +1 Action. At the start of your Buy phase, you may pay $2. If you do, take a Coin token.
Would be good for when you have lots of coin but no +Buy. Otherwise, not very useful. Would probably work at $2 cost.
Housekeeper
Types: Action
Cost: $2+
Trash a card from your hand. Take a Coin token.
When you buy this, you may overpay for it. If you do, at the start of Clean-up, trash a card from your hand or from play per $1 you overpaid.
hmmm, trashing card(s) from play at the end of a turn is nice. I think Mint may be the only official card that does that (and it does it very differently). This should probably say "you may trash a card..." in the overpay effect. nice and simple, I like it.
Sculptor
Types: Action
Cost: $5
+1 Action. You may discard 2 cards. If you do, name 2 cards and reveal the top 3 cards of your deck. For each revealed card you named, take a Coin token and put that card on your deck. Discard the rest.
Interesting. I like it, but I think it'd be better at $4 cost.
Tavern
Types: Action
Cost: $4
+1 Action. +$2. Trash a card from your hand. Pay a Coin token. If you have no Coin tokens, gain a Curse. If you gained a Curse, take 3 Coin tokens.
It needs rewording as eHalcyon said. I like the tradeoff of the effect when you have no coin tokens, but I don't like that it makes you pay a coin token in exchange for nothing. But then it gives you a total of +5 buying power if you don't have coin tokens, so maybe it's worth it.
Potter
Types: Action
Cost: $4+
Take 2 Coin tokens. You may pay up to 5 Coin tokens. For each Coin token you paid beyond the first, gain a card costing up to $4.
When you buy this, you may overpay for it. If you do, take a Coin token, then play this.
I kindof like the top, but the overpay effect is overpowered.
Other cards I like that I don't have much to say about: Taskmaster, Barber, Builder.
Cards I kindof like but probably not enough to vote for: Pawnbroker, Councilman, Demagogue, Town Hall, Bookkeeper, Bribe, Tavern, Potter (I only like it without the overpay effect).