As an additional cost to cast instant and sorcery spells, you may pay {X}, where X is that spell's mana value. If you do, copy that spell, and you may choose new targets for the copy.
Spellcharge 4

Menace
Whenever Gelthis deals combat damage to a player, that player reveals their hand. You choose a nonland card from it. Exile that card until Gelthis leaves the battlefield.
Spellcharge 4

If you have more life than your starting life total, this spell costs {X} less to cast, where X is equal to the difference.
Trample
When Glacier Guardian enters, you may have it fight target creature you don't control.

Lifelink
When Gleaming Pathlighter enters, exile up to one target card from a graveyard.

Haste
Whenever you cast a spell that targets Glint-Glyph Oracle, you may discard a card. If you do, draw two cards if Glint-Glyph Oracle is attacking or draw a card otherwise.

At the beginning of combat on your turn, if you've spent at least five mana to cast spells this turn, put a +1/+1 counter on Goldrune Scribe.

This spell costs {3} more to cast if it's your turn.
Target creature gets -2/-2 until end of turn. If it's your turn, it gets -5/-5 until end of turn instead.

Enchant creature
When Grasp of the Yeti enters, you may destroy target creature with flying, artifact, or enchantment.
Enchanted creature gets +3/+3.

Flash
When Grasping Ancient enters, exile up to one target instant or sorcery spell.
Whenever Grasping Ancient attacks, you may cast the exiled card without paying its mana cost.
Spellcharge 4

Whenever Grazing Yaks becomes tapped, if you have at least 3 life more than your starting life total, put a +1/+1 counter on it.
{T}: You gain 1 life.

Search your library for a basic land card, put it into the battlefield tapped, then shuffle. If this spell's flashback cost was paid, search your library for a land card rather than a basic land card.
Flashback—{G}, Sacrifice a land.

Flash
Gulping Meqmaw's power is equal to the total number of permanents with flash you control and instant cards in your graveyard.
Whenever you cast a spell during an opponent's turn, mill two cards.

Lifelink
Pay the equip cost of an Equipment you control: Return Gutwrenched Martyr from your graveyard to the battlefield with a finality counter on it. Attach that Equipment to it. Activate only as a sorcery.

Target creature you control deals damage equal to its power to target creature. If this spell's flashback cost was paid, it deals that much damage to target player instead.
Flashback {4}{R}

When Harvesting Blade enters, target opponent exiles two cards from their hand.
Equipped creature gets +2/+1 and has “When this creature dies, you may cast a card exiled with Harvesting Blade with equal or lesser mana value without paying its mana cost.”
Equip {3}

Vigilance
{T}: Add {C}.
{1}, {T}: Add one mana of any color.
Spellcharge 2

Flash
When Hazard Blade enters, destroy target creature an opponent controls that was dealt damage this turn.
Equipped creature get +4/+0.
Equip {5}

As an additional cost to cast creature spells, you may pay {X}, where X is Heartbonder's power. When you do, put a +1/+1 counter on Heartbonder.

When Hearty Roughrider enters or leaves the battlefield, you gain life equal to the greatest toughness among creatures you control.
Wander {4}{G}{G}

At the beginning of combat on your turn, if you have at least 3 life more than your starting life total, untap target land.

{2}, Sacrifice Helm of the Shattered Realm: Destroy target artifact or enchantment. Activate only as a sorcery.
Equipped creature gets +1/+1 and has ward {2}.
Equip {1}

Defender
When Herald of Awakening enters, draw a card. Then discard a card unless you control a Ruin.
Whenever a Ruin you control becomes spellcharged, Herald of Awakening loses defender until end of turn.

At the beginning of your end step, if you cast no spells this turn, surveil 1.
Spellcharge 6

Lifelink
As long as you have at least 3 life more than your starting life total, each creature you control with toughness greater than its power assigns combat damage equal to its toughness rather than its power.

Vigilance
Whenever another creature entering the battlefield under your control causes an ability of a permanent you control to trigger, put a +1/+1 counter on that creature and you gain 1 life. This ability triggers only once each turn.