Squirrel Mob

Squirrel Mob gets +1/+1 for each other Squirrel on the battlefield.

Krosan Beast

Threshold — Krosan Beast gets +7/+7 as long as seven or more cards are in your graveyard.

Scurrid Colony

Reach
Scurrid Colony gets +2/+2 as long as you control eight or more lands.

Helica Glider

Helica Glider enters with your choice of a flying counter or a first strike counter on it.

Canyon Jerboa

Landfall — Whenever a land you control enters, creatures you control get +1/+1 until end of turn.

Minsc, Beloved Ranger

When Minsc, Beloved Ranger enters, create Boo, a legendary 1/1 red Hamster creature token with trample and haste.
{X}: Until end of turn, target creature you control has base power and toughness X/X and becomes a Giant in addition to its other types. Activate only as a sorcery.