msem-instigator

When Greenheart Squirrel enters, look at the top four cards of your library. You may reveal a basic land card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Whenever Greenscale Bully deals combat damage to a player, create a Treasure token. (It's an artifact with “{T}, Sacrifice this permanent: Add one mana of any color.”)

{T}: Add one mana of any color.
Paranoia {G} (You may cast this spell for its paranoia cost when a permanent you control leaves the battlefield.)

Trample

When Greypelt Clergy enters, choose one —
• Put a +1/+1 counter on Greypelt Clergy.
• Permutate. (You may remove a counter from a creature you control. If you do, put two +1/+1 counters on a different creature you control.)

Whenever another Hound you control enters, put a +1/+1 counter on Greypelt Initiate.

Trample
Greypelt Ruffian gets +1/+1 as long as you control a storied permanent. (Enchantments and legendary permanents are storied.)

{1}, {T}: Search your library for a card named Greypelt Trooper, reveal it, put it into your hand, then shuffle. Activate only as a sorcery.

Menace
Disgraced 1 (This enters with a -1/-1 counter. Whenever it deals combat damage to a player, remove all -1/-1 counters from it.)

This spell costs {2} less to cast if a permanent you controlled left the battlefield this turn.
Target creature gets +3/+0 and gains trample until end of turn.

Flying, haste
Whenever Grieving Revenant attacks, it deals 1 damage to each other creature you control.

When Grievous Buccaneer enters, it voyages. (If it isn't blocking or targeted by another spell or ability, it phases out.)
Whenever Grievous Buccaneer phases in, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Griffin Skycaller enters, target creature you control gets +1/+1 and gains flying until end of turn.

Flying, lifelink

As an additional cost to cast this spell, tap an untapped artifact or creature you control.
Up to three target creatures can't block this turn.

When Grim Botanist enters, create a 1/1 green Saproling creature token.
Whenever a nontoken creature you control dies, populate. (Create a token that's a copy of a creature token you control.)

Destroy target creature or planeswalker. Create a Treasure token.

{T}, Sacrifice Grim Courtyard: Search your library for a Swamp or Forest card and put it onto the battlefield tapped, then shuffle.

Whenever another Citizen you control dies, you gain 2 life.
{2}{B}, Exile a Citizen card from your graveyard: Each opponent loses 2 life.

When Grim Procession enters, create two 2/2 black Zombie creature tokens.
{2}{B}: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Target player sacrifices a creature. Create a tapped 2/2 black Zombie creature token.

Equipped creature gets +1/+0 and has wither. (It deals damage to creatures in the form of -1/-1 counters.)
Equip {2}

{2}, {T}: Create a Treasure token. (It's an artifact with “{T}, Sacrifice this permanent: Add one mana of any color.”)
{W}{U}{B}{R}{G}, {T}, Sacrifice Grim's Warchest: Exile target creature.

Enchant creature
Enchanted creature has experience. (Whenever it attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)