Argothian Opportunist

When Argothian Opportunist enters, create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Kogla, the Titan Ape

When Kogla, the Titan Ape enters, it fights up to one target creature you don't control.
Whenever Kogla attacks, destroy target artifact or enchantment defending player controls.
{1}{G}: Return target Human you control to its owner's hand. Kogla gains indestructible until end of turn.

Atarka Beastbreaker

Formidable — {4}{G}: Atarka Beastbreaker gets +4/+4 until end of turn. Activate only if creatures you control have total power 8 or greater.