MtG keyword: Ransom
Ransom: When this creature deals damage to a player, exile target artifact or creature card that player controls for as long as you control it.
2 Colorless: Return a card exiled in this way to the battlefield under its owner's control. Any player may activate this ability.
Example cards:
Nuln, Collector of Debts (2BW)
Legendary Creature - Clerical Cleric
Ransom: When this creature deals damage to a player, exile target artifact or creature card that player controls for as long as you control Nuln, Collector of Debts.
2 Colorless: Return a card exiled in this way to the battlefield under its owner's control. Any player may activate this ability.
Ward 2
1BW: Nuln, Collector of Debts 1 damage to each opponent.
1/5
Swarthy Kidnapper (2BB)
Creature - Pirate Ninja
Ransom
Ninjutsu (2B) (Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
2/2
Repossession Agent (2B)
Creature - Human Accountant
Fear
Ransom
When an opponent activates the Ransom ability of a creature you control, create a treasure token.
1/1
Mind's Eye Extortionist (3U)
Creature - Bird Wizard
Flying
Ransom
When an opponent activates the Ransom ability of a creature you control, look at the top card of their deck. You may place it on the bottom of their library.
1/2
And so on.
There could be equipment and Auras that give Ransom, White/Black synergies with cards like Blood Artist and the like, etc.
Trying to bring to life the idea of a Syndicate/Church/Mob that slows opponents down while profiting off of nickeling and dimming them over their own cards.