Cat Collector

When this creature enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
Whenever you gain life for the first time during each of your turns, create a 1/1 white Cat creature token.

Savannah Lions

Hinterland Sanctifier

Whenever another creature you control enters, you gain 1 life.

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.

Union of the Third Path

Draw a card, then you gain life equal to the number of cards in your hand.

Adventurer's Inn

When this land enters, you gain 2 life.
{T}: Add {C}.

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.

Joust Through

Joust Through deals 3 damage to target attacking or blocking creature. You gain 1 life.

Lifecreed Duo

Flying
Whenever another creature you control enters, you gain 1 life.

Inspiring Overseer

Flying
When this creature enters, you gain 1 life and draw a card.

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.

Ossification

Enchant basic land you control
When this Aura enters, exile target creature or planeswalker an opponent controls until this Aura leaves the battlefield.

Ajani's Pridemate

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

Helpful Hunter

Banishing Light

When this enchantment enters, exile target nonland permanent an opponent controls until this enchantment leaves the battlefield.