Derevi, Empyrial Tactician

Flying
When Derevi enters and whenever a creature you control deals combat damage to a player, you may tap or untap target permanent.
{1}{G}{W}{U}: Put Derevi onto the battlefield from the command zone.

Black Panther, Wakandan King

First strike
Survey the Realm — Whenever Black Panther or another creature you control enters, put a +1/+1 counter on target land you control.
Mine Vibranium — {3}: Move all +1/+1 counters from target land you control onto target creature. If one or more +1/+1 counters are moved this way, you gain that much life and draw a card.

Sauron, the Dark Lord

Ward—Sacrifice a legendary artifact or legendary creature.
Whenever an opponent casts a spell, amass Orcs 1.
Whenever an Army you control deals combat damage to a player, the Ring tempts you.
Whenever the Ring tempts you, you may discard your hand. If you do, draw four cards.

Zurgo Stormrender

Mobilize 1 (Whenever this creature attacks, create a tapped and attacking 1/1 red Warrior creature token. Sacrifice it at the beginning of the next end step.)
Whenever a creature token you control leaves the battlefield, draw a card if it was attacking. Otherwise, each opponent loses 1 life.

Y'shtola, Night's Blessed

Vigilance
At the beginning of each end step, if a player lost 4 or more life this turn, you draw a card.
Whenever you cast a noncreature spell with mana value 3 or greater, Y'shtola deals 2 damage to each opponent and you gain 2 life.

Toph, the First Metalbender

Nontoken artifacts you control are lands in addition to their other types. (They don't gain the ability to {T} for mana.)
At the beginning of your end step, earthbend 2. (Target land you control becomes a 0/0 creature with haste that's still a land. Put two +1/+1 counters on it. When it dies or is exiled, return it to the battlefield tapped.)

Nekusar, the Mindrazer

At the beginning of each player's draw step, that player draws an additional card.
Whenever an opponent draws a card, Nekusar deals 1 damage to that player.

Aang, Master of Elements

Flying
Spells you cast cost {W}{U}{B}{R}{G} less to cast.
At the beginning of each upkeep, you may transform Aang, Master of Elements. If you do, you gain 4 life, draw four cards, put four +1/+1 counters on him, and he deals 4 damage to each opponent.

Avatar Aang

Flying, firebending 2
Whenever you waterbend, earthbend, firebend, or airbend, draw a card. Then if you've done all four this turn, transform Avatar Aang.

Avatar Aang // Aang, Master of Elements

Indoraptor, the Perfect Hybrid

Bloodthirst X (This creature enters with X +1/+1 counters on it, where X is the damage dealt to your opponents this turn.)
Menace
Enrage — Whenever Indoraptor is dealt damage, choose an opponent at random. Indoraptor deals damage equal to its power to that player unless they sacrifice a nontoken creature of their choice.

Captain America, First Avenger

Throw ... — {3}, Unattach an Equipment from Captain America: He deals damage equal to that Equipment's mana value divided as you choose among one, two, or three targets.
... Catch — At the beginning of combat on your turn, attach up to one target Equipment you control to Captain America.

Teval, the Balanced Scale

Flying
Whenever Teval attacks, mill three cards. Then you may return a land card from your graveyard to the battlefield tapped.
Whenever one or more cards leave your graveyard, create a 2/2 black Zombie Druid creature token.

Prossh, Skyraider of Kher

When you cast this spell, create X 0/1 red Kobold creature tokens named Kobolds of Kher Keep, where X is the amount of mana spent to cast it.
Flying
Sacrifice another creature: Prossh gets +1/+0 until end of turn.