So far Unicorn Overlord is my top pick for GOTY, but I still have a LOT of games to play before I can provide an authoritative opinion. Another contender: Shiren the Wanderer: The Mystery Dungeon of Serpentcoil Island.
And a few others that fall just short of GOTY consideration: Lil’ Guardsman, Contra: Operation Galuga, and Super Monkey Ball: Banana Rumble.