msem-instigator

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.

Whenever you cast a spell during an opponent's turn, put a charge counter on Gift of the Sphinx.
At the beginning of your upkeep, draw a card for each charge counter on Gift of the Sphinx.

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

Create a 2/2 colorless Spirit creature token.
Draw a card.

When Gilded Authority enters, create two Treasure tokens. (They're artifacts with “{T}, Sacrifice this artifact: Add one mana of any color.”)
Creatures your opponents control get -1/-0.

When Gitaxian Reprocessor enters, if you cast it, choose one —
• Create a token that's a copy of another target creature, except it's an artifact and isn't a creature.
• Create a token that's a copy of target noncreature artifact, except it's a 2/2 creature in addition to its other types.

You may pay {U} and tap an untapped Rogue you control rather than pay this spell's mana cost.
Counter target spell unless its controller pays {2}.

Enchant creature
Enchanted creature doesn't untap during its controller's untap step.
Untap each Horror you control during enchanted creature's controller's untap step.

Flying, prowess
{T}: Until end of turn, target land is every basic land type in addition to its other types.

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

Flying

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.

{T}, Pay 1 life: Add {U}.
{T}, Pay 1 life, Sacrifice Gleaming River: Search your library for an Island card, put it onto the battlefield tapped, then shuffle.

When Gleeful Deviser enters, create a 1/1 colorless Construct artifact creature token.

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

Aetherize target creature you control. (To aetherize, create a token that's a copy of it, then exile that token.)
Draw a card.

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.

Glitch {2} (Remove one [restriction] for each time you pay the glitch cost.)
Draw two cards. [Then discard two cards.]

Draw three cards. Discard your hand at the beginning of the next end step.

Return target nonland permanent to its owner's hand. If you control an Elemental, draw a card.

Look at the top two cards of your library. Put one of them into your hand and the other into your graveyard.
Flashback {2}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Flying (This creature can't be blocked except by creatures with flying or reach.)
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

At the beginning of your upkeep, scry 1.
At the beginning of combat on your turn, if you cast both a creature spell and a noncreature spell this turn, you may have Glintwing Nest become a 4/4 Elemental Bird creature with flying in addition to its other types until end of turn.

When Globule of Intuition enters or leaves the battlefield, scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)
{2/U}, {T}, Sacrifice Globule of Intuition: Draw a card.

When Gluttonous Empath enters, gain control of target nonland permanent for as long as you control Gluttonous Empath.