Tom Bombadil Maybe Im being sentimental, especially since you arent likely to use Tom Bombadil as anything other than a 5-color commander
If the opponent has managed to evolve into high HP Pokmon, you can always put damage counters on the opponents board, then use Devolution to turn these high HP Pokmon back into their low HP Basic or Stage 1 forms (Kirlia, Charmander, etc.)
Rocco, Street Chef It surprised me to learn that Rocco, Street Chef is a popular commander, but after realizing you can go infinite with cards like Eternal Scourge and either Jinnie Fay, Jetmir's Second or Rest in Peace, I understand the appeal
Heres how to play Disney Lorcana online so youve always got someone to have a match with
Even away from that format, these cards help you pull ahead of your opponents and bury them beneath a verdant force that Overruns them