This list is of my most wanted forms. If you do them, you'll probably get into my good books for doing so.

Deku/Goron/Zora Thorn (Zelda series)
Lady of the Lake Thorn (Sonic Black Knight)
Thorn Dragon (Mythology)
Rozalin Thorn (Disgaea)
Pikachu Thorn (Pokemon, Actual or Cosplay)
Magus Thorn (Chrono Tigger)
Silvia Thorn (Viewtiful Joe)