These are all the Pokemon with more than 2 evolution methods (besides Eevee).
Slowpoke: level up, king's rock, Galarica cuff, Galarica wreath (arguably only 2 for each form)
Tyrogue: level up with physical attack > physical defense, level up with physical attack < physical defense, level up with physical attack = physical defense
Burmy: level up female with plant cloak, level up female with sandy cloak, level up female with trash cloak, level up male (arguably only 2 because all Wormadams are the same species)
Applin: tart apple, sweet apple, syrupy apple
source
So the one with the most methods is either Slowpoke or Burmy, depending on how you count forms. Milotic is also worth mentioning for having 2 evolution methods that both evolve into the same Pokemon.
