A few ideas; not worth a thread
Drawbridge
Action - $3
+1 Buy
+1 Card per Buy you have
Showroom
Action/Reaction - $4
Gain a card costing up to $1 per card in your hand
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Before a card leaves your hand on another player's turn, you may first play this card from your hand
Clarification: Leave=trash, discard, play, set aside, put on top of your deck etc.
Craft Show
Action - $2
+3 Actions
You may gain a non-Victory card costing exactly $1 per Action you have (Action, not Action card)
Spyglass
Treasure - $4
Worth $0
When you play this, do both, and choose one that each other player may do:
Gain a Silver; Look through your discard pile and put a treasure from it into your hand
Blacksmith
Action - $5
+3 Cards
Discard a card. If it's a(n)
Action: +2 Actions
Treasure: +$2
Victory card: +2 Cards
Florist
Action/Reaction - $4
+1 Action
You may play any number of Coppers from your hand. Then, draw until you have 4 cards in hand
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When you would gain a card, you may reveal this from your hand to, instead, gain a Copper to your hand
Opportunist
Action - $3
When you gain, play or trash this, +1 Card and you may trash a card from your hand.