Prideful Parent

Vigilance (Attacking doesn't cause this creature to tap.)
When this creature enters, create a 1/1 white Cat creature token.

Regal Caracal

Other Cats you control get +1/+1 and have lifelink. (Damage dealt by those creatures also causes you to gain that much life.)
When this creature enters, create two 1/1 white Cat creature tokens with lifelink.

Helpful Hunter

Claws Out

This spell costs {1} less to cast for each Cat you control.
Creatures you control get +2/+2 until end of turn.

Skyknight Squire

Whenever another creature you control enters, put a +1/+1 counter on this creature.
As long as this creature has three or more +1/+1 counters on it, it has flying and is a Knight in addition to its other types.

Ajani's Pridemate

Whenever you gain life, put a +1/+1 counter on this creature.

Progenitor Exarch

When Progenitor Exarch enters, incubate 3 X times. (To incubate 3, create an Incubator token with three +1/+1 counters on it and "{2}: Transform this artifact." It transforms into a 0/0 Phyrexian artifact creature.)
{T}: Transform target Incubator token you control.

Soul-Guide Lantern

When this artifact enters, exile target card from a graveyard.
{T}, Sacrifice this artifact: Exile each opponent's graveyard.
{1}, {T}, Sacrifice this artifact: Draw a card.

Arahbo, the First Fang

Other Cats you control get +1/+1.
Whenever Arahbo or another nontoken Cat you control enters, create a 1/1 white Cat creature token.

Felidar Cub

Sacrifice this creature: Destroy target enchantment.

Plains

Leonin Vanguard

At the beginning of combat on your turn, if you control three or more creatures, this creature gets +1/+1 until end of turn and you gain 1 life.

Savannah Lions

Lay Down Arms

Exile target creature with mana value less than or equal to the number of Plains you control. Its controller gains 3 life.