Avatar of the Resolute

Reach, trample
Avatar of the Resolute enters the battlefield with a +1/+1 counter on it for each other creature you control with a +1/+1 counter on it.

Thought Gorger

Trample
When Thought Gorger enters the battlefield, put a +1/+1 counter on it for each card in your hand. If you do, discard your hand.
When Thought Gorger leaves the battlefield, draw a card for each +1/+1 counter on it.

Conjurer's Closet

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.

Nikara, Lair Scavenger

Partner with Yannik, Scavenging Sentinel (When this creature enters the battlefield, target player may put Yannik into their hand from their library, then shuffle.)
Menace
Whenever another creature you control leaves the battlefield, if it had one or more counters on it, you draw a card and you lose 1 life.

Cathars' Crusade

Whenever a creature enters the battlefield under your control, put a +1/+1 counter on each creature you control.

Aura Shards

Whenever a creature enters the battlefield under your control, you may destroy target artifact or enchantment.

Shalai, Voice of Plenty

Flying
You, planeswalkers you control, and other creatures you control have hexproof.
{4}{G}{G}: Put a +1/+1 counter on each creature you control.

Eternal Witness

When Eternal Witness enters the battlefield, you may return target card from your graveyard to your hand.

Yannik, Scavenging Sentinel

Partner with Nikara, Lair Scavenger
Vigilance
When Yannik, Scavenging Sentinel enters the battlefield, exile another creature you control until Yannik leaves the battlefield. When you do, distribute X +1/+1 counters among any number of target creatures, where X is the exiled creature's power.

Meadowboon

When Meadowboon leaves the battlefield, put a +1/+1 counter on each creature target player controls.
Evoke {3}{W} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters the battlefield.)

Restoration Angel

Flash
Flying
When Restoration Angel enters the battlefield, you may exile target non-Angel creature you control, then return that card to the battlefield under your control.

Juniper Order Ranger

Whenever another creature enters the battlefield under your control, put a +1/+1 counter on that creature and a +1/+1 counter on Juniper Order Ranger.

Bloodtracker

Flying
{B}, Pay 2 life: Put a +1/+1 counter on Bloodtracker.
When Bloodtracker leaves the battlefield, draw a card for each +1/+1 counter on it.

Incubation Druid

{T}: Add one mana of any type that a land you control could produce. If Incubation Druid has a +1/+1 counter on it, add three mana of that type instead.
{3}{G}{G}: Adapt 3. (If this creature has no +1/+1 counters on it, put three +1/+1 counters on it.)

Bloom Hulk

When Bloom Hulk enters the battlefield, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Abzan Ascendancy

When Abzan Ascendancy enters the battlefield, put a +1/+1 counter on each creature you control.
Whenever a nontoken creature you control dies, create a 1/1 white Spirit creature token with flying.

Good-Fortune Unicorn

Whenever another creature enters the battlefield under your control, put a +1/+1 counter on that creature.

Wayward Swordtooth

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
You may play an additional land on each of your turns.
Wayward Swordtooth can't attack or block unless you have the city's blessing.

Gyre Sage

Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
{T}: Add {G} for each +1/+1 counter on Gyre Sage.

Thragtusk

When Thragtusk enters the battlefield, you gain 5 life.
When Thragtusk leaves the battlefield, create a 3/3 green Beast creature token.

Reveillark

Flying
When Reveillark leaves the battlefield, return up to two target creature cards with power 2 or less from your graveyard to the battlefield.
Evoke {5}{W} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters the battlefield.)

Winding Constrictor

If one or more counters would be put on an artifact or creature you control, that many plus one of each of those kinds of counters are put on that permanent instead.
If you would get one or more counters, you get that many plus one of each of those kinds of counters instead.