Seht's Tiger [The List] Sliver you gain life equal to

you gain life equal to that creature's converted mana cost

"Gix failed

but I believe a more mundane power source might suffice

Set: Commander 2018 Type: Enchantment Rarity: Rare Cost: {2}{U} You may have Estrid's Invocation enter the battlefield as a copy of an enchantment you control

Seht's Tiger [The List] Sliver you gain life equal toSet: The List Type: Creature Cat Rarity: Rare Cost: {2}{W}{W} Flash (You may play this spell any time you could play an instant.) When Seht's Tiger comes into play, you gain protection from the color of your choice until end of turn. (You can't be targeted, dealt damage, or enchanted by anything of the chosen color.)