There are a few spells that I would like to see. I'll make note of some personal favorites.

Arboreal Storm - Dryad (North Shroud)
Blood Rain - Camilla (Masked Carnival - Beauty and the Beast)

Choco Kick - Wild Chocobo (The Dravanian Forelands)
Lumisphere - Vouivre (The Churning Mists)

Aetherial Spark - Salt Dhruva (The Lochs)
Shadow Burst - Creeping Edila (The Lochs)