Need theme for a card game

My partner suggested an idea for a weird little mechanic in a brainstorming session for another project but we rejected it. I wanted to come back to it for something else, and the start of a card game was born.

Funny thing is, I got really far with the mechanic without ever applying a theme so we have this abstract skeleton of a game without any story or reasoning behind it whatsoever. What we need is to hear ideas for themes that could fit the mechanic.

The game revolves around 4 players laying down cards from their hand that modify a test roll that is taken at the completion of the round. The result of the test roll determines which if any players pick up the trick (or part of it), with the object being to NOT pick up cards. Scoring will take place with certain cards and card sequences counting against the player holding them, with the possibility of some cards being neutral or even beneficial.

The players aren't really in conflict with each other directly and can play cooperatively or not so the theme needs to reflect this. The players are sort of "against an unseen mutual enemy", but gain or lose as a result of their own strategic choices. The extent to which they gain or lose depends on the play of others.

If you've got an idea for a theme that might fit something like this, I'd love to hear it with the exception of zombies, post-apoc, orks, and anything else over-done. I'm open-minded to anything else as long as it's not nutty for the sake of excessive nuttiness. Or maybe not; I guess I am willing to listen to crazy.

Tob