...elements and elemental spirits. (Western, eastern, scientific, or other sets of elements are welcome. Western elemental spirits are most famous but others are fine too.)
A Poetry Fishbowl is poetry written approximately to spec -- you give her a prompt, she'll write a poem. She may combine prompts from more than one person in a given piece. You'll get a copy (via email) of the poem written to your prompt, and she'll post a comment with the title and a short description, including cost.
She usually posts one free poem per month as a teaser. If you sponsor a poem (can be any poem listed, doesn't have to be the one written for you), she will post it on her journal as a separate entry, and you receive non-exclusive reprint rights, which means you can re-post it (with proper credit, of course!) in your journal or blog.
Go feed the fish! If at least one new person posts a prompt or sponsors a poem, ysabetwordsmith will post an additional free poem.