Mistbreath Elder

At the beginning of your upkeep, return another creature you control to its owner's hand. If you do, put a +1/+1 counter on this creature. Otherwise, you may return this creature to its owner's hand.

Blade of Selves

Equipped creature has myriad. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Equip {4}

Caller of the Untamed

Before you shuffle your deck to start the game, you may reveal this card from your deck and exile a creature card you drafted that isn't in your deck.
{X}, {T}: Create a token that's a copy of a card you exiled with cards named Caller of the Untamed. X is the mana value of that card.

Bramble Sovereign

Whenever another nontoken creature enters, you may pay {1}{G}. If you do, that creature's controller creates a token that's a copy of that creature.

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Temur Sabertooth

{1}{G}: You may return another creature you control to its owner's hand. If you do, this creature gains indestructible until end of turn.

Conjurer's Closet

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.

Lizard, Connors's Curse

Trample
Lizard Formula — When Lizard, Connors's Curse enters, up to one other target creature loses all abilities and becomes a green Lizard creature with base power and toughness 4/4.

Cloudstone Curio

Whenever a nonartifact permanent you control enters, you may return another permanent you control that shares a permanent type with it to its owner's hand.

Helm of the Host

At the beginning of combat on your turn, create a token that's a copy of equipped creature, except the token isn't legendary. That token gains haste.
Equip {5}

Dinosaur Headdress

When this Equipment enters, attach it to target creature you control.
As this Equipment becomes attached to a creature, choose an exiled creature card used to craft this Equipment.
Equipped creature is a copy of the last chosen card.
Equip {2}

Paleontologist's Pick-Axe

Whenever equipped creature attacks, draw a card, then discard a card.
Equip {1}
Craft with one or more creatures {5} ({5}, Exile this artifact, Exile one or more creatures you control and/or creature cards from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)