Well Rested

The whole payoff hinges on a word most Auras never touch: untap. Almost every enchantment that pumps a creature keys off entering the battlefield, attacking, or the beginning of your turn; this one waits for the creature to become untapped, then dispenses a stacked reward package (two counters, two life, a card) capped at once per turn. That trigger placement is the design tension. On a stock creature it fires during your untap step, but only if the creature actually tapped the turn before, so the engine wants a body that attacks, taps for an ability, or otherwise spends itself and then stands back up. The real build-around comes when you own the untapping mid-turn: anything that untaps a permanent as a cost or an effect turns Well Rested into an engine that draws and gains life the moment you want it, not once a cycle. The once-per-turn clamp is what pays for that; without it, chaining untap effects would loop the draw and life gain into a combo rather than a value curve. It rewards you for treating untapping as a resource, an axis green rarely asks you to sequence around, since green's own untap effects usually exist to reuse mana dorks. The counters make the enchanted creature harder to answer while the card draw refuels the hand, but the honest read is that it wants a deck already thinking about when and how its creatures stand back up.