Loot, the Pathfinder

Double strike, vigilance, haste
Exhaust — {G}, {T}: Add three mana of any one color. (Activate each exhaust ability only once.)
Exhaust — {U}, {T}: Draw three cards.
Exhaust — {R}, {T}: Loot deals 3 damage to any target.

Aetherdrift Promos

Aetherdrift

Double strike, vigilance, haste
Exhaust — {G}, {T}: Add three mana of any one color.
Exhaust — {U}, {T}: Draw three cards.
Exhaust — {R}, {T}: Loot deals 3 damage to any target.

Exhaust abilities can be activated any time you could normally activate an ability.

If an ability triggers whenever you activate an exhaust ability, that ability resolves before the exhaust ability resolves.

If an exhaust ability of a permanent is activated, and then that permanent leaves the battlefield and returns to the battlefield, it becomes a new object so its exhaust ability can be activated again.