Here’s a new (to me) form that sounds like it's a spell from the Harry Potter series of books: Rimas Dissolutas!
Rimas Dissolutas Poems
Popular with 12th and 13th century French poets, rimas dissolutas is a poem that rhymes and doesn't rhyme. For instance, each stanza contains no end rhymes, but each line in each stanza rhymes with the corresponding line in the next stanza--sometimes employing an envoi at the end.
For example, here's how the end rhymes would work in a rimas dissolutas with three five-line stanzas:
(If the poem had an envoi, it might be 2-3 lines long using the c, d, and/or e rhymes.)
Note: There are no rules for meter, line length, or syllables--except that it should be consistent from stanza to stanza.
Play with poetic forms!
Poetic forms are fun poetic games, and this digital guide collects more than 100 poetic forms, including more established poetic forms (like sestinas and sonnets) and newer invented forms (like golden shovels and fibs).
Here’s my attempt at Rimas Dissolutas:
the cat of sadness, by Robert Lee Brewer
the cat of sadness does not purr
late at night anymore or hunt
for creatures to offer up still
half-alive & held in her teeth
oblivious to trembling furr
focused on performing her stunt
& pleasing her king on the hill
who loved her above & beneath
but who left her for a new thrill
as she curled up into a wreath