All the plants that can instantly kill any zombie other than the zombies absorbing more than 1800 damage per shot.
Note: When an instant-kill plant is utilized, it immediately disappears (excluding Squashes, Cob Cannon missiles, Tangle Kelps, Chili Beans or Imitater instant kills).
Cherry Bombs, Jalapenos, Squashes, Potato Mines, Doom-shrooms, And Cob Cannon missiles, all do 1800 damage, killing any zombies except for zombies which absorb more than 1800 damage. Primal Potato Mines deal 2400 damage, and can defeat any zombie except for Robo-Cone Zombies, Gargantuars, and Zombot Dinotronic Mechasaur. The Tangle Kelp kills any zombie instantly regardless of health, and the same applies to the Chomper, Chili Bean, and Toadstool, except for when attacking Gargantuars and bosses.