I don't have one.
In that case your choice defaults to Mima's charged bodyslam from SoEW.
For me, I think Yumeko's swordspam is pretty fun, even if it eats through your
bombs lives continues as if they were nothing on lunatic. :V
As for actual spellcards, there's alot of fun ones to choose from. Hm, let's just go with Radiant Treasure.
Hounorable mention to Small Demon's Arrival, because I still have no clue how that card works.