Solitary Sanctuary

Stun counters usually read as a defensive tool: a way to buy a turn by locking a blocker or attacker out of its next untap step. Here that tempo swing is wired directly into an offensive engine. The enter trigger neutralizes one creature, and the standing ability turns every subsequent tap of an opponent's untapped creature into a growth trigger, so an attacker that pins down blockers is simultaneously feeding a +1/+1 counter onto your own board. The second ability does not restrict itself to combat, either: any effect that taps down an opposing creature counts, which means tapping for value (to disable a mana source or clear a blocker before the swing) doubles as a pump. What keeps it from spiraling is that both halves need an opponent's creature to work against. Against an empty board the enchantment is a dead permanent, and the growth trigger only fires on creatures that were actually untapped, so a defensive opponent who leaves everything tapped starves the engine. It is a design that rewards a wide, tap-heavy shell where the incidental taps you were already generating suddenly build a threat, folding a piece of soft removal and an anthem-adjacent payoff into the same three-mana enchantment.