I voted Panicking Alla Mambo, because it's got a cute design and basically any level with them is guaranteed as a win, which, as I'm going through my hackless palette runs, is a miracle every time I get one with a good chip on it. That said I think Springing Spicatto, Swarming Languendo, and Homing Arpeggio are also VERY cute designs and I like them a lot.
Also Asychronous Rondo. Panopticons are very very cool as video game locations and having a panopticon boss that's literally just a giant spinning searchlight that screams at you is FANTASTIC. Also another guaranteed win lol, I don't think I've died to any boss except Pinging Marciale