Cauldron
Types: Treasure, Attack, Doom
Cost: $4
$3. When you play this, receive a Hex. If you gain or trash a card this way, each other player gains a Curse.
Even with the Hex every time you play this, it still seems pretty strong for a $4 Gold. Compare to Contraband and Cache, which are $5 Golds and come with pretty gnarly drawbacks, even with Contraband giving you the +Buy. As you mentioned yourself, one-third of the Hexes will end up Cursing your opponents, while another fourth basically won't affect you at all (and with smart play, Haunting could actually be used to your advantage).
Contraband gives you a +Buy which needs to accelerate you sufficiently that you don't care about not being able to buy something, while
Cache gives you a one-time drawback of Coppers, and both are considered among the worst $5 cards in the game.
Contraband would probably only survive a second edition because naming stuff is fun. Cauldron hits you with Hexes of random efficacy every time you play it. The Cursing is mostly to soften the blow of how otherwise devastating
War and
Locusts can be. A Cauldron without the Attack would be as bad as
Cursed Gold and would probably never be bought, let alone if it cost $5.
Also, just to be clear with Envy, am I right in assuming the Envious state would take effect on the next turn because, assuming you play Cauldron during your current Buy phase, it has to wait until the start of a Buy phase to take effect?
You are correct. The
Envious and
Deluded States trigger "at the start of your Buy phase," which has already passed by the time Cauldron gives it to you.
Truffle Pig
Cost: $6
Types: Treasure, Duration
$1. At the start of your next turn, +$2, then put this into your hand, then trash a card from your hand.
I think the repeating trashing is neat, but at a cost of $6 it might be a frustratingly swingy card. Players will miss or hit it on turns 3\4 with fairly little control. It is certainly strong enough to cost $6, but a cost of $5 might be healthier.
Pelt
Cost: $2
Types: Treasure, Traveller
+$1. You may discard a Victory card from your hand for +1 Buy.
When you discard this from play, you may exchange it for a Promise.
Promise
Cost: $3*
Types: Treasure, Traveller
+$1. Reveal the top card of your deck. If it is a Treasure, play it. Otherwise, you may discard it or put it back.
When you discard this from play, you may exchange it for a Hacksilver.
Hacksilver
Cost: $4*
Types: Treasure, Traveller
+2 Coffers
When you discard this from play, you may exchange it for a Promissory Note.
Promissory Note
Cost: $5*
Types: Treasure, Traveller
+$2. Draw two more cards for your next hand.
When you discard this from play, you may exchange it for an Interest.
Interest
Cost: $6*
Types: Treasure, Duration
Now and at the start of each of your turns: +$2, +1 Buy.
I'd worry that whenever this is relevant, it will just be a race for 2 or 3 Interests.
Teacher and
Champion both rely quite strongly on other Action cards, while Interest is a fairly static source of economy.
Vagabond
Types: Night, Traveller
Cost: $2
Trash a card from your hand.
When you discard this from play, you may exchange it for a Burglar.
Burglar
Types: Night, Attack, Traveller
Cost: $3*
+1 Coffers. Gain a Treasure costing up to $4. Each other player discards a Treasure (or reveals a hand with no Treasures).
When you discard this from play, you may exchange it for a Wanted Criminal.
Wanted Criminal
Types: Night, Attack, Traveller
Cost: $4*
Reveal a card costing up to $6 from your hand. Either each other player gains a copy of it, or you do, your choice.
When you discard this from play, you may exchange it for a Crime Lord.
Crime Lord
Types: Night, Attack, Traveller
Cost: $5*
+3 Coffers. Each other player takes their -$1 token.
When you discard this from play, you may exchange it for an Underground Market.
Underground Market
Types: Night, Duration
Cost: $6*
At the start of each of your turns for the rest of the game: +1 Buy.
While this is in play, cards cost $1 less on your turns.
Between both Traveller lines, +Buys like +Coffers, so I like that you can get them from separate parts of their lines. I like Underground Market more since +Buys also combo with cost reduction (though it should mention that cards can't cost less than $0). I'm not sure that I like Vagabond or Wanted Criminal very much though. Vagabond is a trasher that can deal with itself in largely the way
Raze does, so it helps you speed up exchanging the Traveller (as opposed to
Peasant which is pretty slow and
Page whose
Treasure Hunter and
Hero actively slow you down). Wanted Criminal can combo with Underground Market to gain Provinces, and otherwise I think is mostly a wild game accelerator since you can use it to pile multiplayer games out super easily.
By the way, does anyone care about the
Herbalist tracking issues with Duration Treasures?