Scute Mob

At the beginning of your upkeep, if you control five or more lands, put four +1/+1 counters on this creature.

Ageless Entity

Whenever you gain life, put that many +1/+1 counters on this creature.

Centaur Battlemaster

Heroic — Whenever you cast a spell that targets this creature, put three +1/+1 counters on this creature.

Needletooth Pack

Morbid — At the beginning of your end step, if a creature died this turn, put two +1/+1 counters on target creature you control.

Mild-Mannered Librarian

{3}{G}: This creature becomes a Werewolf. Put two +1/+1 counters on it and you draw a card. Activate only once.

Experiment One

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Remove two +1/+1 counters from this creature: Regenerate it. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Ridgescale Tusker

When this creature enters, put a +1/+1 counter on each other creature you control.

Servant of the Scale

This creature enters with a +1/+1 counter on it.
When this creature dies, put X +1/+1 counters on target creature you control, where X is the number of +1/+1 counters on this creature.

Kalonian Hydra

Trample
This creature enters with four +1/+1 counters on it.
Whenever this creature attacks, double the number of +1/+1 counters on each creature you control.

Agonasaur Rex

Trample
Cycling {2}{G} ({2}{G}, Discard this card: Draw a card.)
When you cycle this card, put two +1/+1 counters on up to one target creature or Vehicle. It gains trample and indestructible until end of turn.

Cloakwood Swarmkeeper

Gathered Swarm — Whenever one or more tokens you control enter, put a +1/+1 counter on this creature.

Hero of Leina Tower

Heroic — Whenever you cast a spell that targets this creature, you may pay {X}. If you do, put X +1/+1 counters on this creature.

Grunn, the Lonely King

Kicker {3} (You may pay an additional {3} as you cast this spell.)
If Grunn was kicked, it enters with five +1/+1 counters on it.
Whenever Grunn attacks alone, double its power and toughness until end of turn.

Moldgraf Millipede

When this creature enters, mill three cards, then put a +1/+1 counter on this creature for each creature card in your graveyard. (To mill three cards, put the top three cards of your library into your graveyard.)

Stampeding Scurryfoot

Exhaust — {3}{G}: Put a +1/+1 counter on this creature. Create a 3/3 green Elephant creature token. (Activate each exhaust ability only once.)

Whiptongue Hydra

Reach
When this creature enters, destroy all creatures with flying. Put a +1/+1 counter on this creature for each creature destroyed this way.

Ancient Imperiosaur

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Trample, ward {2}
This creature enters with two +1/+1 counters on it for each creature that convoked it.

Conclave Sledge-Captain

Backup 1, backup 1, backup 1 (When this creature enters, put a +1/+1 counter on target creature. If that's another creature, it gains the following abilities until end of turn. Each backup ability triggers separately.)
Trample
Whenever this creature deals combat damage to a player, put that many +1/+1 counters on it.

Heroes' Bane

This creature enters with four +1/+1 counters on it.
{2}{G}{G}: Put X +1/+1 counters on this creature, where X is its power.

Karok Wrangler

Magecraft — Whenever you cast or copy an instant or sorcery spell, put a +1/+1 counter on target creature you control.

Snapping Sailback

Flash
Enrage — Whenever this creature is dealt damage, put a +1/+1 counter on it. (It must survive the damage to get the counter.)

Cragplate Baloth

Kicker {2}{G}
This spell can't be countered.
Hexproof, haste
If this creature was kicked, it enters with four +1/+1 counters on it.

Herd Baloth

Whenever one or more +1/+1 counters are put on this creature, you may create a 4/4 green Beast creature token.

Battlefront Krushok

This creature can't be blocked by more than one creature.
Each creature you control with a +1/+1 counter on it can't be blocked by more than one creature.

Foe-Razer Regent

Flying
When this creature enters, you may have it fight target creature you don't control.
Whenever a creature you control fights, put two +1/+1 counters on it at the beginning of the next end step.

Toadstool Admirer

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
{3}{G}: Put a +1/+1 counter on this creature.