Brimaz, King of Oreskos

Vigilance
Whenever Brimaz, King of Oreskos attacks, create a 1/1 white Cat Soldier creature token with vigilance that's attacking.
Whenever Brimaz blocks a creature, create a 1/1 white Cat Soldier creature token with vigilance that's blocking that creature.

Arahbo, Roar of the World

Eminence — At the beginning of combat on your turn, if Arahbo, Roar of the World is in the command zone or on the battlefield, another target Cat you control gets +3/+3 until end of turn.
Whenever another Cat you control attacks, you may pay {1}{G}{W}. If you do, it gains trample and gets +X/+X until end of turn, where X is its power.

Kaheera, the Orphanguard

Companion — Each creature card in your starting deck is a Cat, Elemental, Nightmare, Dinosaur, or Beast card. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
Vigilance
Each other creature you control that's a Cat, Elemental, Nightmare, Dinosaur, or Beast gets +1/+1 and has vigilance.

Ajani, Caller of the Pride

+1: Put a +1/+1 counter on up to one target creature.
−3: Target creature gains flying and double strike until end of turn.
−8: Create X 2/2 white Cat creature tokens, where X is your life total.

Ajani, Adversary of Tyrants

+1: Put a +1/+1 counter on each of up to two target creatures.
−2: Return target creature card with mana value 2 or less from your graveyard to the battlefield.
−7: You get an emblem with "At the beginning of your end step, create three 1/1 white Cat creature tokens with lifelink."

Jazal Goldmane

First strike (This creature deals combat damage before creatures without first strike.)
{3}{W}{W}: Attacking creatures you control get +X/+X until end of turn, where X is the number of attacking creatures.

Jedit Ojanen of Efrava

Forestwalk (This creature can't be blocked as long as defending player controls a Forest.)
Whenever Jedit Ojanen of Efrava attacks or blocks, create a 2/2 green Cat Warrior creature token with forestwalk.

Adorned Pouncer

Double strike
Eternalize {3}{W}{W} ({3}{W}{W}, Exile this card from your graveyard: Create a token that's a copy of it, except it's a 4/4 black Zombie Cat with no mana cost. Eternalize only as a sorcery.)