yeah sure i'll bite. Here's one that works with captain, workshop, etc as kind of an inverse cost reducer. It's not always gonna be worthwhile (when there's no cards that select by price on the board) but workshopping grand markets sounds pretty chill.
edit: fixed to remove some ambiguity
What exactly does "select" mean here? What does "selecting" a card costing $2 more actually do?
so take a peek at Workshop - "Gain a card costing up to $4" - this is selecting a card from the supply that costs up to $4, then gaining it. This lets you select a card costing up to $6 with it.
Or consider Smugglers. If you have this project, your opponent bought a province last turn, you can smuggle a province.
figured out a cleaner way to phrase the card (i'll change the actual image on monday when im not working off a phone):
During your Action phase, cards everywhere cost $2 less (to a minimum of $0).
Note that this way (unlike the action phase phrasing* I suggested above / earlier), would no longer work with your example of Smugglers.
[
EDIT: this is incorrect. Smugglers will work just fine - it's TfB that will work differently than the original wording.]
* "During your Action phase, all cards in the Supply cost
less (but not less than
)."
But if you prefer this way, you can also drop the "everywhere", it's clearly implied and none of the official cards use it.
EDIT: Just realized another problem. This works very differently with TFB (makes many of them significantly worse), which is common enough to make that an issue. Although then you could just not buy Shipworker's Union, so it's probably fine.
Maybe it's my turn to miss something, but I'm missing how it would make many TfB significantly worse. For example, play remodel, trash an estate, gain a gold. (Estate from hand still costs $2, gold from supply costs $6).