Gideon's Reproach

Gideon's Reproach is legal in Commander, Legacy, Modern, Pioneer, Vintage, Pauper, and Oathbreaker, but its combat restriction keeps it off most competitive lists in any of those formats. In Pauper it sees the most daylight, where aggressive white decks occasionally want cheap interaction that punishes attackers, though even there it competes with removal that isn't conditional. In Commander, four damage rarely finishes a creature once the game hits mid-range, and the attacking-or-blocking clause means it sits dead against the biggest threats on the table. The formats where conditional damage at two mana could matter are formats where better options exist at the same cost.