Oketra’s Last Mercy 1WW
Your life total becomes equal to your starting life total. Lands you control don’t untap during your net untap step.
Now this is life gain.
This is obviously Commander playable. Seedborn Muse makes the “self exert” cost nothing. Plus there’s plenty of untapping in Commander. Or you could even Omniscience it out and it doesn’t matter what your lands are doing.
Oketra’s Last Mercy could even Standard/Modern playable. Sideboard it in against Naya Burn. About to die and they’re out of gas? Boom, back at 20. Just don’t get blown out by a Skullcrack in response.
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