Free verse
From the French vers libre. Free verse is poetry whose lines follow no consistent meter. It may be rimed, but usually is not.
Prose poetry
Poetic language printed in prose paragraphs, but displaying the careful attention to sound, imagery, and figurative language characteristic of poetry.
Concrete poetry
A visual poetry composed exclusively for the page in which a picture or image is made of printed letters and words. Concrete poetry attempts to blur the line between language and visual objects, usually relying on puns and cleverness.