1) Character demand and artwork Popular Pokmon (Charizard, Umbreon, Rayquaza, Mewtwo, Gengar) tend to command higher prices across all eras
Lands Building a good manabase in Commander can be tricky
Hopeless Nightmare - Why it Was Banned in MTG's Standard Format Perhaps not as problematic as other cards on this list, Hopeless Nightmare is still very frustrating to play against due to strategies that bounce it back to the owner's hand from play or the graveyard, making it a consistently strong 1-drop for Orzhov Pixie decks in Standard
If a monster specifies its materials as Level 8 or higher, any combination that is Level 8 or higher can be used
Bumbleflower is the real MVP here
They could ban Vivi in Standard, in which case everyone who spent a lot of money on Vivi cards (currently going for like 40-55 bucks each as of this writing) would be pissed off, although Id argue that if you bought Vivi knowing what was happening you factored that in as a possibility