Stifle

In Legacy, Stifle is a staple — pairing it with Wasteland to strand opponents on one land while denying the fetchland's ability is a well-established tempo line. Vintage allows it as well, where stifling a Moxen activation or a fast combo trigger is plausible but less central than in Legacy. Commander is where the calculus shifts: one target among four players means Stifle is situational, but the format's reliance on powerful triggered abilities — landfall, aristocrats engines, extra-turn spells, combat triggers — gives it real utility in reactive or control shells. It doesn't belong in every blue Commander deck, but any deck that expects to police the table's most dangerous triggers will find it punches well above its mana cost.