Trollbred Guardian

{2}{G}: Adapt 2. (If this creature has no +1/+1 counters on it, put two +1/+1 counters on it.)
Each creature you control with a +1/+1 counter on it has trample.

Leader's Talent

(Gain the next level as a sorcery to add its ability.)
Whenever you attack, put a +1/+1 counter on target attacking creature.
{2}{W}: Level 2
Whenever a creature you control leaves the battlefield, if it had a counter on it, you gain 2 life.
{3}{W}: Level 3
Whenever you cast a spell, put a +1/+1 counter on each creature you control.

Loading Zone

If one or more counters would be put on a creature, Spacecraft, or Planet you control, twice that many of each of those kinds of counters are put on it instead.
Warp {G} (You may cast this card from your hand for its warp cost. Exile this enchantment at the beginning of the next end step, then you may cast it from exile on a later turn.)

Venus, Torn Between Worlds

Whenever Venus is dealt damage, put that many +1/+1 counters on her. (She must survive the damage to get the counters.)
Whenever a creature you control with a counter on it deals combat damage to a player, you may pay {U}. If you do, draw a card.

The Ooze

Whenever a creature you control with a +1/+1 counter on it leaves the battlefield, create a Mutagen token for each +1/+1 counter on it. (A Mutagen token is an artifact with "{1}, {T}, Sacrifice this token: Put a +1/+1 counter on target creature. Activate only as a sorcery.")
{T}: Exile target card from a graveyard. Create a Mutagen token.

Terrasymbiosis

Whenever you put one or more +1/+1 counters on a creature you control, you may draw that many cards. Do this only once each turn.

Ouroboroid

At the beginning of combat on your turn, put X +1/+1 counters on each creature you control, where X is this creature's power.

Parallel Lives

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

Drix Fatemaker

When this creature enters, put a +1/+1 counter on target creature.
Each creature you control with a +1/+1 counter on it has trample.
Warp {1}{G} (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)

Mikey & Leo, Chaos & Order

Whenever you put a counter on a creature you control, draw a card. This ability triggers only once each turn.

Raphael, the Muscle

Double all damage that creatures you control with counters on them would deal.
When Raphael enters, create a Mutagen token.
Partner—Character select (You can have two commanders if both have this ability.)

Leonardo, the Balance

Whenever a token you control enters, you may put a +1/+1 counter on each creature you control. Do this only once each turn.
{W}{U}{B}{R}{G}: Creatures you control gain menace, trample, and lifelink until end of turn.
Partner—Character select (You can have two commanders if both have this ability.)

Michelangelo, Weirdness to 11

When Michelangelo enters, create a Mutagen token. (It's an artifact with "{1}, {T}, Sacrifice this token: Put a +1/+1 counter on target creature. Activate only as a sorcery.")
If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.

The Earth Crystal

Green spells you cast cost {1} less to cast.
If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on that creature instead.
{4}{G}{G}, {T}: Distribute two +1/+1 counters among one or two target creatures you control.

Corpsejack Menace

If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on it instead.

Resourceful Defense

Whenever a permanent you control leaves the battlefield, if it had counters on it, put those counters on target permanent you control.
{4}{W}: Move any number of counters from target permanent you control onto a second target permanent you control.

Primal Vigor

If one or more tokens would be created, twice that many of those tokens are created instead.
If one or more +1/+1 counters would be put on a creature, twice that many +1/+1 counters are put on that creature instead.

Haliya, Ascendant Cadet

Whenever Haliya enters or attacks, put a +1/+1 counter on target creature you control.
Whenever one or more creatures you control with +1/+1 counters on them deal combat damage to a player, draw a card.

Agent Bishop, Man in Black

At the beginning of combat on your turn, put a +1/+1 counter on each of up to two target creatures.

Michelangelo, the Heart

Trample
Raid (the Fridge) — At the beginning of your second main phase, if you attacked this turn, put a +1/+1 counter on target creature and create a Food token.
Partner—Character select (You can have two commanders if both have this ability.)

Savanti Romero, Time's Exile

Trample
At the beginning of combat on your turn, put a +1/+1 counter on Savanti Romero. Then you draw X cards and lose X life, where X is the number of counters on Savanti Romero.