msem-instigator

When Goblin Twinblades enters, create a 1/1 red Goblin creature token.

When Godseeker Vanguard enters, create two 1/1 green Scout creature tokens.

Golden Company Valiant can block any number of creatures.
At the beginning of combat on each opponent's turn, Golden Company Valiant gets +1/+1 until end of turn for each creature that player controls.

When Golna, the First Shah enters, create Shir, a legendary 3/3 white Cat creature token with trample.
Monument {5}{G}{G} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

Haste (This creature can attack and {T} as soon as it comes under your control.)
Motivate 2 (When this creature enters, you may motivate target creature with less power than this by putting two +1/+1 counters on it.)

Whenever a creature enters under an opponent's control, you may pay 2 life. If you do, draw a card.

Flash
If a +1/+1 counter would be put on another creature, that counter is put on Grafted Physician instead.

When Grave Reaper enters, if it wasn't cast from your hand, it gets +1/+1 until end of turn.
Unearth {B} ({B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the end step or if it would leave the battlefield. Unearth only as a sorcery.)

Menace
Augmented — When Gravitational Ripper enters, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, target opponent sacrifices a creature. If they can't, they discard a card.

When Graygulch Drifter enters, return target creature card from your graveyard to your hand. If that card is a Spirit, you may return an additional Spirit card from your graveyard to your hand.

When Green Daywalker enters, you may destroy target artifact or enchantment.
Augmented — At the beginning of each end step, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on Green Daywalker.

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.”)

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.)

Flying, lifelink

{B}, {T}, Exile two cards from your graveyard: Create a 1/1 white Spirit creature token with flying.

Flying, vigilance
When Guardian Grotesque dies, return up to one target nonland permanent to its owner's hand.
Foreshadow {6} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

First strike
Whenever Guardian of the Eclipse attacks, you may exile another target attacking creature you control, then return it to the battlefield under your control tapped and attacking.

When Guardian of the Wurm enters, create a 6/6 green Wurm creature token with trample.

Flash
When Guppyfin Duelist enters, create a green Aura enchantment token named Piranha's Prowess attached to target creature. The token has enchant creature and “Enchanted creature gets +2/+2.” Untap that creature.

When Gusma's Artisan enters, search your library for a card, then shuffle and put that card on the bottom of it.
{2}{U}, Sacrifice Gusma's Artisan: Manifest the bottom card of your library. (To manifest a card, put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

Prowess
Gusma's Emissary gets +1/+1 as long as you control a black or green permanent.