Aven Riftwatcher

Flying
Vanishing 3 (This creature enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When this creature enters or leaves the battlefield, you gain 2 life.

Time Spiral Remastered

Flying
Vanishing 3 (This creature enters the battlefield with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When Aven Riftwatcher enters the battlefield or leaves the battlefield, you gain 2 life.

The List

Eternal Masters

Planar Chaos

Flying
Vanishing 3 (This permanent comes into play with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When Aven Riftwatcher comes into play or leaves play, you gain 2 life.