Sidisi, Undead Vizier

Deathtouch
Exploit (When this creature enters, you may sacrifice a creature.)
When Sidisi, Undead Vizier exploits a creature, you may search your library for a card, put it into your hand, then shuffle.

Grim Giganotosaurus

{10}{B}{G}: Monstrosity 10. This ability costs {1} less to activate for each creature with power 4 or greater your opponents control. (If this creature isn't monstrous, put ten +1/+1 counters on it and it becomes monstrous.)
When Grim Giganotosaurus becomes monstrous, destroy all artifacts and creatures other than Grim Giganotosaurus.

Henry Wu, InGen Geneticist

Henry Wu, InGen Geneticist and other Human creatures you control have exploit. (When a creature with exploit enters, you may sacrifice a creature.)
Whenever a creature you control exploits a non-Human creature, draw a card. If the exploited creature had power 3 or greater, create a Treasure token.

Mindleech Ghoul

Exploit (When this creature enters, you may sacrifice a creature.)
When Mindleech Ghoul exploits a creature, each opponent exiles a card from their hand.

Overcharged Amalgam

Flash
Flying
Exploit (When this creature enters, you may sacrifice a creature.)
When Overcharged Amalgam exploits a creature, counter target spell, activated ability, or triggered ability.