Deranged Hermit

Echo {3}{G}{G} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When this creature enters, create four 1/1 green Squirrel creature tokens.
Squirrel creatures get +1/+1.

Chatterfang, Squirrel General

Forestwalk (This creature can't be blocked as long as defending player controls a Forest.)
If one or more tokens would be created under your control, those tokens plus that many 1/1 green Squirrel creature tokens are created instead.
{B}, Sacrifice X Squirrels: Target creature gets +X/-X until end of turn.

Chatterstorm

Create a 1/1 green Squirrel creature token.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

Squirrel Wrangler

{1}{G}, Sacrifice a land: Create two 1/1 green Squirrel creature tokens.
{1}{G}, Sacrifice a land: Squirrel creatures get +1/+1 until end of turn.

Eldrazi Monument

Creatures you control get +1/+1 and have flying and indestructible.
At the beginning of your upkeep, sacrifice a creature. If you can't, sacrifice this artifact.

Chitterspitter

At the beginning of your upkeep, you may sacrifice a token. If you do, put an acorn counter on this artifact.
Squirrels you control get +1/+1 for each acorn counter on this artifact.
{G}, {T}: Create a 1/1 green Squirrel creature token.

Squirrel Squatters

When this creature enters, open an Attraction. (Put the top card of your Attraction deck onto the battlefield.)
Whenever this creature attacks, create a 1/1 green Squirrel creature token that's tapped and attacking for each Attraction you've visited this turn.

Overrun

Creatures you control get +3/+3 and gain trample until end of turn. (Each of those creatures can deal excess combat damage to the player or planeswalker it's attacking.)