msem-instigator

{1}{U}{R}, {T}: Create a token that's a copy of another target creature, except it's an artifact in addition to its other types and has “Whenever this creature is dealt damage, destroy it.”

When Gemcrusher Turtle enters, choose one —
• Destroy target artifact.
• Gemcrusher Turtle fights up to one target creature.

Whenever you cast a spell with mana value 5 or greater, create an X/1 red Mutant creature token with trample and haste, where X is that spell's mana value. Exile that token at the beginning of the next end step.

Whenever one or more creatures you control attack, create a 1/1 white Human Samurai creature token.

Whenever a creature you control enters, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)
{2}, Sacrifice an Idol: Creatures you control get +1/+1 until end of turn.

Flying, haste
Whenever one or more other nontoken Pirates and/or Rogues you control attack, create a 1/1 red Pirate creature token.

Creatures can't attack you or a planeswalker you control unless their controller pays {2} for each of those creatures.
Creatures can't block Ghastly Scraper unless their controller pays {2} for each of those creatures.

Flash

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever Ghostly Hounds mentors a creature, that creature can't be blocked this turn.

Trample

Tribute 1 (As this creature enters, an opponent of your choice may put a +1/+1 counter on it.)
When Giant Dromad enters, if tribute wasn't paid, you may destroy target artifact or enchantment.

Whenever Gifted Swordsman attacks, upgrade it. (Give it one of the listed counters it doesn't already have.)
• +1/+1
• First strike

When Giku Weaponsmith enters, create two colorless Equipment artifact tokens with “Equipped creature gets +1/+1” and equip {1}.

Renown 2 (When this creature deals combat damage to a player, if it isn't renowned, put two +1/+1 counters on it and it becomes renowned.)
When Gilded Champion becomes renowned, you may search your library for an Equipment or Aura card, reveal it, put it into your hand, then shuffle.

Vigilance, lifelink

Trample
{3}, Discard Gilded Ram: Draw a card, gain 2 life, and create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Menace
Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
Gilded Sell-Sword gets +2/+0 as long as you're in a renaissance.

When Gilded Yak enters, you gain 3 life.

Flash
Players can't discard cards.
Whenever Gim-Chimya, the Invisible attacks, it can't be blocked this turn unless defending player pays {1} for each card in your hand.

Flash
When Giver of Martoob enters, put a +1/+1 counter on each of up to two target creatures you control.

When Gleamhorn Gargantuan enters, put a +1/+1 counter on up to one other target creature.
Cycling {2} ({2}, Discard this card: Draw a card.)

Flying
Whenever an opponent casts a spell, copy it. You may choose new targets for the copy.

Vision (Whenever this or another creature you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Gleaming Rider envisions an instant or sorcery card, target creature becomes a 5/5 Elk Spirit until end of turn.

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Wither (This deals damage to creatures in the form of -1/-1 counters.)
Instant and sorcery spells you control have wither. (They deal damage to creatures in the form of -1/-1 counters.)