Challenge by: reminiscent-afterthought, The Light's Refrain, Aiko Isari, Kaito Lune
This is an expansion/revisioning of the original diversity challenge, with more original writing in mind - but can on the whole still be used for fanfics if you like! Also, prose only prompts here because not everybody likes poetry, and vice-versa. Separate into lengths for the same reason, plus two free length sections. Look at the sub-pages for each individual word count range! Word counts, unless otherwise stated, count for the entire fic/collection/series.
Some prompts are repeated, but they'll be in different sections and so for different lengths.
If you plan to do them all, keep a masterlist somewhere. You're going to need it. :)