Sanctuary Warden

The clever move here is that the shield counters and the payoff engine draw from a single pool, so the card is really two designs negotiating over one resource. The two shields it enters with are pure defense: they eat targeted removal and combat deaths before they touch the body. But every attack and every enter trigger asks you to spend a counter to draw a card and spin off a Citizen, which means the same protection you'd want to hoard is also the fuel you'd want to burn. Cash the shields for cards and bodies and you leave a bare 5/5 flyer exposed; sit on them and forgo the value. The design opens further because the trigger reads counters, not just its own shields, so any counter on any creature or planeswalker you control feeds it, from loyalty to +1/+1 stacks to shields sitting on other permanents. Building around counter accumulation pays off without demanding a dedicated shell, which keeps the card flexible rather than parasitic. A six-mana 5/5 flyer that draws and makes a token on the way in has always been a fair top-end; the wrinkle is that the same clause fires again on every attack, turning one body into a repeatable card-and-token engine so long as you keep feeding it counters to remove.