A Bestiary poem catalogues various sorts of beasties, especially mythical and fantastic critters like dragons, ghosts, unicorns, cyclops, fauns, etc.
Example
Y Ddraig Goch by Jez Farmer
In the mountains and valleys
sleeps the mystical beast
in his rest waiting
to take to the skies
on his proud wings
as his fiery breath burns
and the enemy turns too late
to escape his rage
and just one breath
condemns them to hell
A Garret Poet 