trope_bingo has just started its 14th round. As this is a general amnesty round, participants can generate their own cards or reuse old cards from previous rounds.

I'd also like to rec two other challenges:

allbingo: An extremely flexible bingo community that also hosts monthly bingo fests.

creativechallenges: This community offers lots and lots of prompt tables in several categories (smut, angst, ships, fluff, AUs).

All the communities above are multifandom and open to all kinds of fanwork as well as original works.