Vexing Bauble

Vexing Bauble carries two restrictions worth naming: it only hits spells cast without paying their mana cost, and the punishment is a card draw for the opponent rather than a hard counter. Legacy banned it outright, and Vintage restricts it to a single copy — both formats have enough free-spell density that even a soft tax with card draw upside becomes an oppressive engine. Commander gives it a pass for two reasons: the free-spell ecosystem is narrower in most pods, and the card-draw clause turns into a political tool rather than a runaway advantage, since drawing one card rarely breaks a four-player game the way it breaks a one-on-one match.