msem-instigator

You may return a land you control to its owner's hand rather than pay this spell's mana cost.
Galvan Coal Line enters tapped.
{T}: Add {R}.

As an additional cost to cast this spell, discard a card.
Draw three cards.

Equipped creature has haste.
Whenever equipped creature deals combat damage to a player, discard a card. If you do, draw a card.
Equip {1}

(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.

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

Flash

Trample
Cycling {2} ({2}, Discard this card: Draw a card.)

Once each turn, when you cast a creature spell, you may copy it for each other spell you cast this turn. (A copy of a creature spell becomes a token.)
Whenever Garragrok, Horde Tyrant attacks, add {R}{R}{G}{G}. Until end of turn, you don't lose this mana as steps and phases end.

{2}{G}, Sacrifice a land: Gashing Panther gains indestructible until end of turn. Tap it.

{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.

{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.

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.

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.

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

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

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.

When Gemplate Golem enters or dies, put a +1/+1 counter on target creature you control.

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.

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.)