Pattern of Rebirth

Enchant creature
When enchanted creature dies, that creature's controller may search their library for a creature card, put that card onto the battlefield, then shuffle.

Have

Mitotic Slime

When this creature dies, create two 2/2 green Ooze creature tokens. They have "When this token dies, create two 1/1 green Ooze creature tokens."

Hissing Iguanar

Whenever another creature dies, you may have this creature deal 1 damage to target player or planeswalker.

Jaxis, the Troublemaker

{R}, {T}, Discard a card: Create a token that's a copy of another target creature you control. It gains haste and "When this token dies, draw a card." Sacrifice it at the beginning of the next end step. Activate only as a sorcery.
Blitz {1}{R} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

Zada, Hedron Grinder

Whenever you cast an instant or sorcery spell that targets only Zada, copy that spell for each other creature you control that the spell could target. Each copy targets a different one of those creatures.

Reincarnation

Choose target creature. When that creature dies this turn, return a creature card from its owner's graveyard to the battlefield under the control of that creature's owner.

Caldaia Guardian

Whenever this creature or another creature you control with mana value 4 or greater dies, create two 1/1 green and white Citizen creature tokens.
Blitz {2}{G} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

Vicious Shadows

Whenever a creature dies, you may have this enchantment deal damage to target player equal to the number of cards in that player's hand.

Fecundity

Whenever a creature dies, that creature's controller may draw a card.

Grumgully, the Generous

Each other non-Human creature you control enters with an additional +1/+1 counter on it.

Lesser Masticore

As an additional cost to cast this spell, discard a card.
{4}: This creature deals 1 damage to target creature.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Rage Thrower

Whenever another creature dies, this creature deals 2 damage to target player or planeswalker.

Spiteful Prankster

During your turn, this creature has first strike.
Whenever another creature dies, this creature deals 1 damage to target player or planeswalker.

Hajar, Loyal Bodyguard

Sacrifice Hajar: Legendary creatures you control get +1/+0 and gain indestructible until end of turn.