msem-instigator

(Add a quest counter as this enters. Sacrifice after 5.)
Whenever you cast a spell, add a quest counter.
Discard a card. If you do, draw a card.
Target opponent discards a card, then draws a card. If they discarded a card with greater mana value than each spell you control, remove a quest counter from Gambler's Tournament.
Discard your hand, then draw seven cards.

At the beginning of your upkeep, you win the game if the total mana value of permanents you control is exactly 21. If it's more than 21, sacrifice Gambling Table and all Card tokens you control. Otherwise, create a colorless Card artifact token with mana cost {2} and “{2}, Sacrifice this artifact: Draw a card.”

As Game Trail enters, you may reveal a Mountain or Forest card from your hand. If you don't, Game Trail enters tapped.
{T}: Add {R} or {G}.

(Transform this if it's not attached to a creature. Pay {R} as a sorcery to unattach it.)
Enchant creature you control
Gamhaugen War Swine's rider gets +1/+1 and has haste.

(Transform this if it's not attached to a creature. Pay {3}{U} as a sorcery to unattach it.)
Enchant creature you control
Gamhaugen Warbeast's rider gets +2/+2 and has flying.

Ganzorig's Domain enters tapped.
When Ganzorig's Domain enters, you may mill two cards.
{T}: Add {R} or {G}.

Enchant creature
Enchanted creature gets -1/-1 and can't block.
Enchanted creature gets an additional -1/-1 for each card named Garrote in your graveyard.

{1}, Sacrifice Gasoline Canister: It deals 1 damage to any target. If a creature or planeswalker dealt damage this way would die this turn, exile it instead.

When Gate of Realms enters, you may search your library for a land card, reveal it, and put that card into your hand. If you do, shuffle.
{10}, {T}: Gate of Realms deals 3 damage to any target. This ability costs {1} less to activate for each different name among lands you control.

Whenever you cast a noncreature spell, put a quest counter on Gate to the Beyond.
At the beginning of your upkeep, if there are three or more quest counters on Gate to the Beyond, you draw a card and you lose 1 life. Then if there are six or more quest counters on it, each opponent loses 2 life.

{T}, Pay 2 life: Add {B}.
{T}: Add one mana of any color. Spend this mana only to cast spells from your graveyard or activate abilities of cards in your graveyard.

When Gateway Statues enters, put a +1/+1 counter on target creature you control.
{T}: Add one mana of any color.

Populate, then you gain 2 life. (Create a token that's a copy of a creature token you control.)

(Add a quest counter as this enters. Sacrifice after 3.)
Whenever a creature dies, add a quest counter.
Target player loses 1 life and you gain 1 life.
Put target creature card from a graveyard onto the battlefield under your control.
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Choose a creature type. Reveal cards from the top of your library until you reveal a card of the chosen type. Put that card into your hand and the rest on the bottom of your library in a random order.

Gathering Beacon enters tapped.
{T}: Add {G}.
{2}, {T}, Sacrifice Gathering Beacon: Choose a creature or planeswalker type, then reveal the top five cards of your library. You may put a card of the chosen type into your hand, then put the rest on the bottom in any order.

Create three 1/1 blue Advisor creature tokens.
Monument {2}{G}{U} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

Whenever one or more +1/+1 counters are put on a creature you control, you may search your library for a creature card, reveal it, put it into your hand, then shuffle.

[+1]: Creatures you control get +0/+1 until your next upkeep. Untap those creatures.
[–2]: Put target tapped creature into its owner's library third from the top.
[–7]: You get an emblem with “Whenever a nonland permanent you control is put into a graveyard from the battlefield, each opponent sacrifices a nonland permanent.”

Pressure {1}{U}{U} (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
Draw three cards.

Search your library for three land cards with different names, reveal them, then shuffle. Put one of those cards onto the battlefield, one into your hand, and one into your graveyard.

Prevent all combat damage target creature would deal this turn. You gain life equal to that creature's power.

Enchant opponent
Enchanted player plays with the top card of their library revealed.
Whenever enchanted player casts a spell, you may have them mill a card.

Choose flying, prowess, vigilance, or ward {2}. Create a colorless Equipment artifact token with “Equipped creature has the chosen ability” and equip {2}. (Then exile this card. You may cast the creature later from exile.)

When you cast a creature spell, sacrifice Gemini Cast. If you do, create a token that's a copy of that spell, except the token isn't legendary.