msem-instigator

At the beginning of your upkeep, discard your hand.
{2}: Greater Masticore deals 1 damage to each other creature.
{6}, Exile six other cards from your graveyard: Return Greater Masticore from your graveyard to the battlefield tapped.

Greenheart Den enters tapped.
{T}: Add {G}.
{G}, {T}: Target creature you control gets +1/+1 until end of turn. Activate only as a sorcery and only if you control a green creature.

As Grim Bastion enters, you may pay 2 life. If you don't, Grim Bastion enters tapped.
{T}, Sacrifice Grim Bastion: Search your library for a Swamp or Forest card, put it onto the battlefield, then shuffle.

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

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

{T}, Pay 1 life: Add {B} or {R}.
{1}, {T}, Sacrifice Grim Slums: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

{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.

Grisly Marsh enters tapped unless another player controls a land that could produce {B} or {G}.
{T}: Add {B} or {G}.

You may play Grisly Ruins from your graveyard as long as seven or more cards are in your graveyard.
Grisly Ruins enters tapped.
{T}: Add {B} or {G}.
Cycling {1}{B}{G} ({1}{B}{G}, Discard this card: Draw a card.)

Grizzled Den enters tapped.
{T}: Add {R} or {G}.
{3}{R}{G}: Until end of turn, Grizzled Den becomes a Bear creature with trample in addition to its other types.
Scavenge {4}{R}{G}

{T}: Add {C}.
{T}: Add one mana of any color. Activate only if two or more land cards are in your graveyard.

{T}: Add {C}.
{T}, Exile two cards from your graveyard: Add {B} or {G}.

{T}: Add {C}.
{T}, Exile two cards from your graveyard: Add {R} or {G}.

Guang Shrine enters tapped.
{T}: Add {G} or {W}.
{G/W}, {T}, Sacrifice Guang Shrine: Put a +1/+1 counter on target creature you control. Activate only as a sorcery.

Flying
Whenever you cast a cryptic spell, Guardian of Mysteries becomes a 4/4 Sphinx creature in addition to its other types until end of turn. (Artifacts, enchantments, and modal spells are cryptic.)
{1}, {T}: Scry 2.

Guidestone enters tapped.
{T}: Add {C}.
{2}, Sacrifice Guidestone: Draw a card.

When Gulch Custodian enters, return an artifact you control to its owner's hand.

Whenever H.S.S. Demeter becomes blocked by a creature, gain control of that creature.
Whenever H.S.S. Demeter deals combat damage to a player, draw two cards.
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)

Equipped creature gets +3/+2.
Equip {4}
Hail of Blades's equip ability costs {4} less to activate if it targets an equipped creature.

Puzzlebox (Begin the game with this and another card you own from outside the game in the command zone, locked. That card is face down until you unlock this.)
{1}, Sacrifice two Clues: Unlock Hall of Lost Histories and put the revealed card into your hand.

{T}: Add {C}.
{3}, {T}, Sacrifice Hall of Random Access Memories: Return target artifact, instant, or sorcery card from your graveyard to your hand.

{T}: Add {C}. You gain 1 life.

{T}: Add {C}.
{T}: Add one mana of any color. Activate only if you have a counter.

Flying
At the beginning of your first main phase, you may put any number of land cards from your hand onto the battlefield, then draw a card for each land put onto the battlefield this way.

As Harlowe, Thespian Extraordinaire enters, choose a color and creature type.
Harlowe, Thespian Extraordinaire is the chosen color.
Harlowe, Thespian Extraordinaire is the chosen type in addition to its other types.