Head Troll -
Creature - Troll
Whenever another non-Human creature enters the battlefield under your control, put a +1/+1 counter on ~.
: ~ gains indestructible until end of turn.
1/1

Empty Castle
Land
: Add .
, , Sacrifice ~: Search your library for a land card, put that card onto the battlefield, then shuffle your library.


Next is Ikoria

Crystalscope Sentry
Creature — Human Soldier
Whenever a creature an opponent controls mutates, draw a card.
Cycling
When you cycle this card, exile target creature that's mutated.
"Inexperienced sentries watch the treeline, but with these ever-changing monsters, you need all your senses and every direction."
2/2

Updraft Pteron

Creature -- Dinosaur (U)
Flying
When Updraft Pteron enters the battlefield, you may put a flying counter on target creature.
It launches its prey into the air with focused blasts of wind and gracefully snaps them from the sky.
3/3

Escalate the Stakes
Sorcery
Put a deathtouch counter on each creature.
The bonders represented a third way out of the conflict between humans and the behemoths and that was intolerable.

Arm -
Instant
Put a reach counter or a trample counter on target creature.
Domri took the suggestion to “arm his troops” a bit too literally.

Soilcoiler
Creature — Nightmare Worm
When Soilcoiler enters the battlefield, mill three cards. For each creature card milled this way, put a +1/+1 counter on Soilcoiler. If a creature card with flying is milled this way, put a flying counter on Soilcoiler. Do the same for first strike, deathtouch, hexproof, lifelink, menace, reach, trample, and vigilance.
1/1

Skinning Knife
Artifact — Equipment
Equipped creature gets +1/+0.
Whenever equipped creature deals combat damage to a non-Human creature, put a +1/+1 counter on equipped creature.
Equip

Monster's Den
Land (U)
: Add .
: Add one mana of any color. Spend this mana only to cast a non-Human creature spell.

Mirrodin / New Phyrexia

Porcelain-Mask Rector
Artifact Creature — Cleric
Infect
All damage is dealt to Porcelain-Mask Rector as though its source had infect.
When Porcelain-Mask Rector dies, you gain life equal to the number of -1/-1 counters on it.
"Yes, mistress, perfect me."
1/8

Deranger -
Artifact
Affinity for artifacts
: Each player mills two cards. Add for each land card put into a graveyard this way.

Needlestab Predator
Creature — Vampire
When Needlestab Predator enters the battlefield, remove all counters from target permanent and put that many +1/+1 counters on Needlestab Predator.
It became a race to see whether the ichor could infect and transform the vampire faster than the vampire could drink and digest the ichor.
2/2

Koth's Gambit

Instant (R)
Remove all -1/-1 counters from creatures you control and all poison counters from you. Koth's Gambit deals damage equal to the number of counters removed this way to any target.

Melira's Triumph
Enchantment
Sources with infect deal damage to creatures in the form of +1/+1 counters instead of -1/-1 counters.
A sixth dawn has arrived.

Triple Key -
Artifact
When ~ enters the battlefield, untap target artifact.
, : Untap target artifact.
Sacrifice ~: Untap target artifact.

Razorgrass Fields
Land
: Add . If you control an artifact, add instead.
, Sacrifice Razorgrass Fields: Razorgrass Fields deals 2 damage to target attacking or blocking creature.

Kamigawa

The Savior Dog
Enchantment — Saga
Flash
I - Return target creature you control to its owner's hand. Spells and abilities opponents control can't cause you to sacrifice creatures this turn.
II - Create Isamaru, Hound of Kondo, a legendary 2/2 white Dog creature token.
III - Exile target creature with power 4 or greater.