Also they are probably a bit busted, but whatever
TCG from Upper Deck's website
Choose a Background (You can have a Background as a second commander.) POWER/TOUGHNESS 5/4 ILLUSTRATOR Billy Christian LEGALITIES Standard Future Historic Timeless Gladiator Pioneer Modern Legacy Pauper Vintage Penny Commander Oathbreaker Standardbrawl Brawl Competitivebrawl Alchemy Paupercommander Duel Oldschool Premodern Predh Tlr LANGUAGES EN FR DE IT JP KR PT RU ES ZH-CN ZH-TW RULINGS 2022-06-10 Notably, the triggered ability of Karlach doesn't give you any additional main phases
Keeper of the Light, Whites keeper, allowed you to gain three life, but only if you had less life than target opponent, while its oath, Oath of Lieges was a little more helpful, although it did help both players
These can even be made to last, too, by using end-of-turn effects like Sundial of the Infinite