Mycoloth

Devour 2 (As this creature enters, you may sacrifice any number of creatures. It enters with twice that many +1/+1 counters on it.)
At the beginning of your upkeep, create a 1/1 green Saproling creature token for each +1/+1 counter on this creature.

Sol Ring

Scurry Oak

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

Orochi Hatchery

This artifact enters with X charge counters on it.
{5}, {T}: Create a 1/1 green Snake creature token for each charge counter on this artifact.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Birds of Paradise

Command Tower

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Hardened Scales

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.

Ivy Lane Denizen

Whenever another green creature you control enters, put a +1/+1 counter on target creature.

Ezuri, Claw of Progress

Whenever a creature you control with power 2 or less enters, you get an experience counter.
At the beginning of combat on your turn, put X +1/+1 counters on another target creature you control, where X is the number of experience counters you have.

Island

Sage of Hours

Heroic — Whenever you cast a spell that targets this creature, put a +1/+1 counter on it.
Remove all +1/+1 counters from this creature: For each five counters removed this way, take an extra turn after this one.

Kami of Whispered Hopes

If one or more +1/+1 counters would be put on a permanent you control, that many plus one +1/+1 counters are put on that permanent instead.
{T}: Add X mana of any one color, where X is this creature's power.