River Heralds' Boon

In Commander, River Heralds' Boon shows up almost exclusively in Merfolk tribal decks built around commanders like Kumena, Tyrant of Orazca, where stacking counters on multiple creatures at once translates directly into card draw and tapping synergies. Outside that archetype it has no home — the effect is too small to matter in a 100-card singleton format where every slot competes hard. In Pauper it's legal but sees no play; the format's Merfolk lists are blue-based tempo shells that have no interest in a sorcery-speed-adjacent pump spell at common. Pioneer and Modern Merfolk are likewise cold on it — those decks want lords and interaction, not a conditional two-for-one that doesn't advance the board state meaningfully. Legacy and Vintage don't bother.