Anafenza, Kin-Tree Spirit

Whenever another nontoken creature you control enters, bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)

Dragon Whisperer

{R}: This creature gains flying until end of turn.
{1}{R}: This creature gets +1/+0 until end of turn.
Formidable — {4}{R}{R}: Create a 4/4 red Dragon creature token with flying. Activate only if creatures you control have total power 8 or greater.

Sarkhan, the Dragonspeaker

+1: Until end of turn, Sarkhan becomes a legendary 4/4 red Dragon creature with flying, indestructible, and haste. (He doesn't lose loyalty while he's not a planeswalker.)
−3: Sarkhan deals 4 damage to target creature.
−6: You get an emblem with "At the beginning of your draw step, draw two additional cards" and "At the beginning of your end step, discard your hand."

Mardu Strike Leader

Whenever this creature attacks, create a 2/1 black Warrior creature token.
Dash {3}{B} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

Indatha Crystal

{T}: Add {W}, {B}, or {G}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Hooded Hydra

This creature enters with X +1/+1 counters on it.
When this creature dies, create a 1/1 green Snake creature token for each +1/+1 counter on it.
Morph {3}{G}{G}
As this creature is turned face up, put five +1/+1 counters on it.

Clever Impersonator

You may have this creature enter as a copy of any nonland permanent on the battlefield.

Ugin, the Spirit Dragon

+2: Ugin deals 3 damage to any target.
−X: Exile each permanent with mana value X or less that's one or more colors.
−10: You gain 7 life, draw seven cards, then put up to seven permanent cards from your hand onto the battlefield.

Narset, Enlightened Master

First strike, hexproof
Whenever Narset attacks, exile the top four cards of your library. Until end of turn, you may cast noncreature spells from among those cards without paying their mana costs.

Sorin, Solemn Visitor

+1: Until your next turn, creatures you control get +1/+0 and gain lifelink.
−2: Create a 2/2 black Vampire creature token with flying.
−6: You get an emblem with "At the beginning of each opponent's upkeep, that player sacrifices a creature of their choice."

Stratus Dancer

Flying
Megamorph {1}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)
When this creature is turned face up, counter target instant or sorcery spell.