We have writing prompts and art prompts...this might seem pretty dumb, but would anyone be interested in "singing prompts"? Like, give a topic to sing about, and sing a song with that topic? Just an idea.
I would happily do this for any prompt where I could manipulate the theme to suit an Eminem rap or a musical theatre song, because these are my only areas of vocal talent.
I'd probably lend my voice occasionally for something like this.