msem-instigator

First strike
Creatures with power greater than Gao'Wu, Master Soothsayer's power can't attack.

As long as you control five or more creatures, if you would create a token, you may instead create Hu Li, a legendary 4/4 white Fox Spirit creature token with flying and lifelink.

You may cast Gateblessed Explorer from your graveyard as long as you control three or more creatures.
Whenever another creature dies, each opponent loses 1 life and you gain 1 life.

Flying
{1}, Sacrifice Gearcraft Observer: Look at target player's hand. Draw a card.

When GenTech Architect enters, create a Function token with “Put two +1/+1 counters on a creature you control.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

When GenTech Assistants enters, create an X/X green Mutant creature token.

Once during each of your turns, when you sacrifice a permanent, you may have target opponent lose 3 life unless they sacrifice a nonland permanent or discard a card.

When Generous Hermit dies, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

When Genome Mapper enters, create a Function token with “Create an X/X green Mutant creature token, where X is this spell's mana value.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Deathtouch
When Ghastly Scorpion dies, you draw a card and you lose 1 life.

{T}: Draw a card, then discard a card.
Sacrifice Ghislain, Cryptbreaker: You may cast target creature, instant or sorcery card from your graveyard this turn. If that spell would be put into your graveyard, exile it instead. Activate only during your turn.

Gestalt (When this or another creature enters under your control, you may merge it with the one in play, keeping counters and attachments. They become the permanent on top plus all abilities from under it.)
This creature gets +2/+2 and has trample as long as it's merged with another card or token.

Lifelink

Flying
When Gilded Guardian dies, you may search your library for a legendary card, reveal it, put it into your hand, then shuffle.

Prowess
Gilded Gunman gets +1/+1 as long as you control an artifact.

Flying
Whenever a player shuffles their library, Gilded Wyvern deals 2 damage to that player.

{T}, Discard a card: Draw a card.
Unveil {2}{U}{R} ({2}{U}{R}: Transform this. Unveil only as a sorcery.)

When Ginjiro Chimei enters, you may search your library for a card with an activated ability, put it into your graveyard, then shuffle.
You may cast Ginjiro Chimei from your graveyard by paying 2 life in addition to paying its other costs.

Harmony — Target creature gains flying until end of turn.
When Glamorous Aerialist enters, harmonize. (Trigger up to one harmony of one permanent you control.)

Hexproof
You may have Glen Hunter assign its combat damage as though it weren't blocked.

Prowess
Wither (This deals damage to creatures in the form of -1/-1 counters.)

Flash
Reach
Glimmerbark Treant enters with X +1/+1 counters on it.
When Glimmerbark Treant leaves the battlefield, you gain life equal to its power.

Trial 3 (As you cast this spell, an opponent of your choice may pay 3 life. If they don't, they fail the trial.)
When Glimmering Prosecutor enters, if the trial was failed, create two 1/1 black Devil creature tokens.

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever Glimmerwing Trickster deals combat damage to a player, scry 2.

Flying, lifelink
Menagerie — When Gloomhollow Fluffpuff enters, if there are five or more creature types among creatures you control, you may search your library for a card named Gloomhollow Fluffpuff, reveal it, put it into your hand, then shuffle.