Primal Vigor

If one or more tokens would be created, twice that many of those tokens are created instead.
If one or more +1/+1 counters would be put on a creature, twice that many +1/+1 counters are put on that creature instead.

Kibo, Uktabi Prince

{T}: Each player creates a colorless artifact token named Banana with "{T}, Sacrifice this token: Add {R} or {G}. You gain 2 life."
Whenever an artifact an opponent controls is put into a graveyard from the battlefield, put a +1/+1 counter on each creature you control that's an Ape or a Monkey.
Whenever Kibo attacks, defending player sacrifices an artifact of their choice.

Flopsie, Bumi's Buddy

When Flopsie enters, put a +1/+1 counter on each creature you control.
Each creature you control with power 4 or greater can't be blocked by more than one creature.

Tsunami

Monkey Cage

When a creature enters, sacrifice this artifact and create X 2/2 green Monkey creature tokens, where X is that creature's mana value.

Maskwood Nexus

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

Hardened Scales

If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.