Cat-Gator

Lifelink
When this creature enters, it deals damage equal to the number of Swamps you control to any target.

Abstruse Appropriation

Devoid (This card has no color.)
Exile target nonland permanent. You may cast that card for as long as it remains exiled, and you may spend colorless mana as though it were mana of any color to cast that spell.

Gwyllion Hedge-Mage

When this creature enters, if you control two or more Plains, you may create a 1/1 white Kithkin Soldier creature token.
When this creature enters, if you control two or more Swamps, you may put a -1/-1 counter on target creature.

Absorb Essence

Target creature gets +2/+2 and gains lifelink and hexproof until end of turn. (Then shuffle this card into its owner's library.)

Purging Stormbrood

Flying
Ward—Pay 2 life.
When this creature enters, remove all counters from up to one target creature.

Purging Stormbrood // Absorb Essence

Afterlife Insurance

Creatures you control gain afterlife 1 until end of turn. Draw a card. (When a creature with afterlife 1 dies, create a 1/1 white and black Spirit creature token with flying.)

Isilu, Carrier of Twilight

Flying, lifelink
Each other nontoken creature you control has persist. (When it dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)
At the beginning of your first main phase, you may pay {W}. If you do, transform Isilu.

Eirdu, Carrier of Dawn

Flying, lifelink
Creature spells you cast have convoke. (Your creatures can help cast those spells. Each creature you tap while casting a creature spell pays for {1} or one mana of that creature's color.)
At the beginning of your first main phase, you may pay {B}. If you do, transform Eirdu.

Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight

Suncleanser

When this creature enters, choose one —
• Remove all counters from target creature. It can't have counters put on it for as long as this creature remains on the battlefield.
• Target opponent loses all counters. That player can't get counters for as long as this creature remains on the battlefield.