When Golden Age enters, you may sacrifice a land. If you do, search your library for a land card, put it onto the battlefield, then shuffle.
You've cast a multicolored spell this turn.

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

Amity — Whenever you attack with Growing Gecko and exactly one other creature, they both get +1/+1 until end of turn. When Growing Gecko deals combat damage to a player this combat, you may transform it.

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.

At the beginning of your upkeep, you may exile target multicolored card from your graveyard. You may cast a copy of it this turn.

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}

Choose up to one for each color among blue, black, and red among permanents you control.
• Create two 2/2 colorless Minion creature tokens with decayed.
• You may sacrifice a creature. If you do, draw two cards.
• Until end of turn, creatures lose all abilities.

Each player chooses up to one nontoken, nonland permanent they control. They lose life equal to its mana value. Destroy the rest.

When Heavy Winds enters and whenever you cast a spell, prevent all damage up to one target permanent would deal this turn.

Enchant creature
Enchanted creature gets +1/+1 and has protection from creatures.

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.

Amity — Whenever you attack with Higana and exactly one other creature, create a 3/3 green, blue, and red Dragon creature token. If the other attacking creature was a Dragon, the token has flying. If it also had flying, the token has vigilance. If it also had vigilance, the token has double strike.
{1}{W}: Create Shigana, a legendary 2/2 white Beast creature token with haste.

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.

When Hoenn Champion enters, create a creature token for each of the following characteristics.
• 3/3 white and black Bird with flying, vigilance, and haste.
• 2/4 red Bird Warrior with double strike, vigilance, and haste.
No more than two creatures can attack each combat. No more than two creatures can block each combat.

Ward—Sacrifice a permanent.
Whenever Host of the Neverending Revel enters or attacks, each player sacrifices a nonland, nontoken permanent. For each player who doesn't, you draw a card.

When Hostage Situation enters, target opponent reveals their hand. Exile a nonland card from it and up to one creature card from your graveyard. When Hostage Situation is no longer on the battlefield, return the exiled cards to their owner's hands.

Hundred-Handed Pillars enters tapped.
{T}: Add {W} or {U}.
{7}{W/U}: Hundred-Handed Pillars becomes a 4/6 white and blue Giant creature with vigilance until end of turn. It's still a land. This ability costs {X} less to activate, where X is your devotion to white and blue. Activate only once each turn.

Hyperloop Obelisk enters tapped.
{T}: Add {U}, {B}, or {R}.
{VP}{VP}{VP}{VP}, Discard Hyperloop Obelisk: Untap target creature. It gets +4/+4 until end of turn.

Favored
Whenever Iara, Blessed-Hart attacks, Iara and another target attacking creature gain double strike until end of turn.

{VP}{VP}{VP}: Reveal the top seven cards of your library. You may have Iconic Hologram become a copy of a legendary creature card revealed this way until end of turn. Put the revealed cards on the bottom of your library in a random order.

{X}, {T}, Sacrifice another creature: Create a token that's a copy of target nontoken creature you control other than Identity Forger with mana value X.

Creatures you control that have been a target or the source of a spell or ability you controlled this turn have ward {2}.
Once each turn, when you spend mana to activate an ability, you may gain that much life.
{X}{U}{R}{W}: Idolized Coordinator and another target creature you control each get +X/+X and gain vigilance until end of turn.

Enchant land
Enchanted land is a 4/4 Dryad creature with reach, vigilance, and haste. It's still a land.
When enchanted land dies, return it to its owner's hand.

Trample
When Imperfect Fugisaur enters, you may sacrifice an artifact. If you do, it gains haste until end of turn.
Whenever Imperfect Fugisaur deals combat damage to a player, that player sacrifices an artifact. If they can't, you draw a card.

Imposing Oddity enters with X +1/+1 counters on it.
Whenever Imposing Oddity becomes spellcharged, put a +1/+1 counter on it.
Spellcharge 4
When Imposing Oddity dies, you may put its counters on another target Ruin you control.