Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

Amrou Kithkin

Amrou Kithkin can't be blocked by creatures with power 3 or greater.

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Sadistic Glee

Enchant creature
Whenever a creature dies, put a +1/+1 counter on enchanted creature.

Kithkin Zephyrnaut

Kinship — At the beginning of your upkeep, you may look at the top card of your library. If it shares a creature type with Kithkin Zephyrnaut, you may reveal it. If you do, Kithkin Zephyrnaut gets +2/+2 and gains flying and vigilance until end of turn.

Plains

Swamp

Idyllic Grange

({T}: Add {W}.)
Idyllic Grange enters tapped unless you control three or more other Plains.
When Idyllic Grange enters untapped, put a +1/+1 counter on target creature you control.

Quill-Slinger Boggart

Whenever a player casts a Kithkin spell, you may have target player lose 1 life.

Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

Surge of Thoughtweft

Creatures you control get +1/+1 until end of turn. If you control a Kithkin, draw a card.

Ballyrush Banneret

Kithkin spells and Soldier spells you cast cost {1} less to cast.

Cenn's Heir

Whenever Cenn's Heir attacks, it gets +1/+1 until end of turn for each other attacking Kithkin.

Kithkin Armor

Enchant creature
Enchanted creature can't be blocked by creatures with power 3 or greater.
Sacrifice Kithkin Armor: The next time a source of your choice would deal damage to enchanted creature this turn, prevent that damage.