Deathless Angel

The repeatable indestructibility is the real engine here, and it points outward rather than inward. Most protective abilities on a creature shield the creature itself; this one names any creature, and the activation is cheap enough to fire more than once per turn if the white is available. That reorients the body from a fragile six-drop into a permission-granting fixture: it lets a smaller attacker brawl up the curve without dying, blanks a sweeper for the one creature you most want to keep, or lets a token tap into combat with no fear of trades. The 5/7 frame is built to survive while it does this work, with a back end large enough to block the things its keyword is keeping alive on the other side. The cost is the obvious tension: it is a double-white commitment on a six-mana flyer with no immediate impact beyond a body, so the indestructibility only matters once you have other creatures worth protecting and the mana to spare protecting them. That makes it a payoff card masquerading as a beater, the kind of effect that reads as situational in the abstract and quietly oppressive once the board is wide enough to feed it.