After the Battle of Pitdown, Lady Ursnell fashioned the first such instrument out of Lord Ursnells left leg
The only downside is that it can only be used once during a duel
Then theres cards which switch on when your life total is high, cards which let you spend life like Witherblooms own founder dragon, and cards which retroactively count how much life youve gained this turn
Most of them are Amethyst, but other colors do it with their own spinthe Amber ink Rapunzel - Gifted Artist lets you draw whenever you remove damage counters from one of your characters, while fellow Amber card Julieta Madrigal lets you do so when you play her and "Healing Touch" lets you do so after you remove four damage counters from one of your characters
Lathril, Blade of the Elves Many players' first elf commander is still the most popular by far
Ampharos, its final evolution, often finds itself included in various game iterations like Pokmon HeartGold and SoulSilver, X and Y, and even recent titles like Sword and Shield, where it continues to be a fan favorite for its Mega Evolution, introduced in Generation VI