Seems like the +70 Flinching Resistance (Shadow Mario Sticker) is the best one I've found. Gigantic flinch resistance on someone like Dedede lets you charge up big forward smashes and be a bit greedy/sloppy as you try to hit multiple mobs at once.
Revisist levels on higher difficulty to get the higher-end stickers.
Revisist levels on higher difficulty to get the higher-end stickers.