Oko is currently banned in every single format in the game, save for Vintage and Commander
Cards like Magnezone and Heatran offer unique benefits, but setup time and vulnerability vary
Madison Li Dragon Shadow Dross Skullbomb Dune Drifter Elder Owyn Lyons Emergency Weld Everquill Phoenix Everquill Phoenix Excava, the Risen Past Excavation Elephant Eye of Ojer Taq Fabrication Foundry Fell Gravship Fix What's Broken Fortuitous Find Gastal Thrillroller Ghirapur Ghost Lantern Ghost Lantern Gilded Assault Cart Glissa, the Traitor Goblin Engineer Golbez, Crystal Collector Gollum the Abandoned Grafted Butcher Gustha's Scepter Hanna, Ship's Navigator Harnessed Snubhorn Hero of the Dunes Holistic Wisdom Hourglass of the Lost Icefall Idol of the Deep King Imperial Recovery Unit
So, he's a win con and life gain in one package
As always, thanks for reading!
In practice, that means every Food you crack for life can also refund you with mana later, which is a sneaky way to keep developing while still stabilizing your life total