Case of the Shattered Pact

When this Case enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.
To solve — There are five colors among permanents you control. (If unsolved, solve at the beginning of your end step.)
Solved — At the beginning of combat on your turn, target creature you control gains flying, double strike, and vigilance until end of turn.

Guildmages' Forum

{T}: Add {C}.
{1}, {T}: Add one mana of any color. If that mana is spent on a multicolored creature spell, that creature enters with an additional +1/+1 counter on it.

Awe for the Guilds

Monocolored creatures can't block this turn.

Seal of the Guildpact

As this artifact enters, choose two colors.
Each spell you cast costs {1} less to cast for each of the chosen colors it is.

Spectral Searchlight

{T}: Choose a player. That player adds one mana of any color they choose.

Leyline of the Guildpact

If this card is in your opening hand, you may begin the game with it on the battlefield.
Each nonland permanent you control is all colors.
Lands you control are every basic land type in addition to their other types.

Emergence Zone

{T}: Add {C}.
{1}, {T}, Sacrifice this land: You may cast spells this turn as though they had flash.

Pillar of the Paruns

{T}: Add one mana of any color. Spend this mana only to cast a multicolored spell.

Glass of the Guildpact

Multicolored creatures you control get +1/+1.

Glaive of the Guildpact

Equipped creature gets +1/+0 for each Gate you control and has vigilance and menace. (A creature with menace can't be blocked except by two or more creatures.)
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Niv-Mizzet, Supreme

Flying, hexproof from monocolored
Each instant and sorcery card in your graveyard that's exactly two colors has jump-start. (You may cast that card from your graveyard by discarding a card in addition to paying its other costs. Then exile it.)

Niv-Mizzet, Guildpact

Flying, hexproof from multicolored
Whenever Niv-Mizzet deals combat damage to a player, it deals X damage to any target, target player draws X cards, and you gain X life, where X is the number of different color pairs among permanents you control that are exactly two colors.

Tome of the Guildpact

Whenever you cast a multicolored spell, draw a card.
{T}: Add one mana of any color.

Guildpact Informant

Flying
Whenever this creature deals combat damage to a player or planeswalker, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Gateway Plaza

This land enters tapped.
When this land enters, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Niv-Mizzet Reborn

Flying
When Niv-Mizzet enters, reveal the top ten cards of your library. For each color pair, choose a card that's exactly those colors from among them. Put the chosen cards into your hand and the rest on the bottom of your library in a random order.

Sphinx of the Guildpact

Sphinx of the Guildpact is all colors.
Flying
Hexproof from monocolored (This creature can't be the target of monocolored spells or abilities your opponents control.)

Thespian's Stage

{T}: Add {C}.
{2}, {T}: This land becomes a copy of target land, except it has this ability.

Guardian of the Guildpact

Tablet of the Guilds

As this artifact enters, choose two colors.
Whenever you cast a spell, if it's at least one of the chosen colors, you gain 1 life for each of the chosen colors it is.

Jace, the Living Guildpact

+1: Look at the top two cards of your library. Put one of them into your graveyard.
−3: Return another target nonland permanent to its owner's hand.
−8: Each player shuffles their hand and graveyard into their library. You draw seven cards.

Maze's End

This land enters tapped.
{T}: Add {C}.
{3}, {T}, Return this land to its owner's hand: Search your library for a Gate card, put it onto the battlefield, then shuffle. If you control ten or more Gates with different names, you win the game.