Greenbelt Radical

In Commander, Greenbelt Radical is a legitimate role-player in any green deck that proliferates, stacks counters on multiple creatures, or runs a +1/+1 counter synergy theme — the enter-the-battlefield trigger scales with board size in a way that few two-mana spells can match. Competitive constructed formats are a different story: Modern and Pioneer have faster clocks and tighter redundancy requirements, and Greenbelt Radical's payoff depends too heavily on having several countered creatures in play simultaneously to fit the tempo expectations of those formats. Standard is its most plausible non-Commander home, particularly in dedicated counter synergy shells where the density of countered creatures is high enough to make the enter trigger consistently relevant. Legacy and Vintage are non-starters — the effect doesn't come close to the power bar those formats set.