Katara, Bending Prodigy

At the beginning of your end step, if Katara is tapped, put a +1/+1 counter on her.
Waterbend {6}: Draw a card. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for {1}.)

Starport Security

{3}{W}, {T}: Tap another target creature. This ability costs {2} less to activate if you control a creature with a +1/+1 counter on it.

The Cabbage Merchant

Whenever an opponent casts a noncreature spell, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
Whenever a creature deals combat damage to you, sacrifice a Food token.
Tap two untapped Foods you control: Add one mana of any color.

Katara, the Fearless

If a triggered ability of an Ally you control triggers, that ability triggers an additional time.

Organic Extinction

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Destroy all nonartifact creatures.

Katara, Heroic Healer

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
When Katara enters, put a +1/+1 counter on each other creature you control.

Weapons Manufacturing

Whenever a nontoken artifact you control enters, create a colorless artifact token named Munitions with "When this token leaves the battlefield, it deals 2 damage to any target."

Katara, Water Tribe's Hope

Vigilance
When Katara enters, create a 1/1 white Ally creature token.
Waterbend {X}: Creatures you control have base power and toughness X/X until end of turn. X can't be 0. Activate only during your turn. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for {1}.)

Exalted Sunborn

Flying, lifelink
If one or more tokens would be created under your control, twice that many of those tokens are created instead.
Warp {1}{W} (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)

Fungal Colossus

This spell costs {X} less to cast, where X is the number of differently named lands you control.

Umbral Collar Zealot

Sacrifice another creature or artifact: Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Lightless Evangel

Whenever you sacrifice another creature or artifact, put a +1/+1 counter on this creature.

Fumigate

Destroy all creatures. You gain 1 life for each creature destroyed this way.

Weftstalker Ardent

Whenever another creature or artifact you control enters, this creature deals 1 damage to each opponent.
Warp {R} (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)

Ragost, Deft Gastronaut

Artifacts you control are Foods in addition to their other types and have "{2}, {T}, Sacrifice this artifact: You gain 3 life."
{1}, {T}, Sacrifice a Food: Ragost deals 3 damage to each opponent.
At the beginning of each end step, if you gained life this turn, untap Ragost.

Chain Reaction

Chain Reaction deals X damage to each creature, where X is the number of creatures on the battlefield.

Emergency Eject

Destroy target nonland permanent. Its controller creates a Lander token. (It's an artifact with "{2}, {T}, Sacrifice this token: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.")

Terrasymbiosis

Whenever you put one or more +1/+1 counters on a creature you control, you may draw that many cards. Do this only once each turn.

Radiant Strike

Destroy target artifact or tapped creature. You gain 3 life.

Ouroboroid

At the beginning of combat on your turn, put X +1/+1 counters on each creature you control, where X is this creature's power.