There aren't many! I looked it up on NoveList Plus on MEL. I use it most every day I work. (I want everyone to use it so MEL will continue providing it!) It returned 80 results with "fantasy poetry" keyword search after I narrowed it to teen and fiction. Once I further narrowed the genre to "novels in verse" It dropped way down to 6. Only four of them were actually fantasy.
- Finding Baba Yaga: a short novel in verse By: Yolen, Jane
- Thin places By: Choyce, Lesley
- Meet me in the fourth dimension By: Feinstein, Rita
- The ghosts of Rose Hill By: Romero, R. M.
Between Toni's answer and this one, hopefully you can find one your patron will enjoy.
Head of Teen Services
Traverse Area District Library
610 Woodmere Ave.
Traverse City MI, 49686
231-932-8500 ext. 275