Forest

Azorius Signet

Arcum's Astrolabe

({S} can be paid with one mana from a snow source.)
When Arcum's Astrolabe enters, draw a card.
{1}, {T}: Add one mana of any color.

Sol Ring

Hulking Metamorph

Prototype {2}{U}{U} — 3/3 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
You may have Hulking Metamorph enter as a copy of an artifact or creature you control, except it's an artifact creature in addition to its other types, and its power and toughness are equal to Hulking Metamorph's power and toughness.

Tinker

As an additional cost to cast this spell, sacrifice an artifact.
Search your library for an artifact card, put that card onto the battlefield, then shuffle.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Balance

Each player chooses a number of lands they control equal to the number of lands controlled by the player who controls the fewest, then sacrifices the rest. Players discard cards and sacrifice creatures the same way.

Channel

Until end of turn, any time you could activate a mana ability, you may pay 1 life. If you do, add {C}.

Elvish Spirit Guide

Exile Elvish Spirit Guide from your hand: Add {G}.

Sol Talisman

Suspend 3—{1} (Rather than cast this card from your hand, pay {1} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
{T}: Add {C}{C}.

Thoughtcast

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Draw two cards.

Prismatic Lens

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

Solve the Equation

Search your library for an instant or sorcery card, reveal it, put it into your hand, then shuffle.

Everflowing Chalice

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
Everflowing Chalice enters with a charge counter on it for each time it was kicked.
{T}: Add {C} for each charge counter on Everflowing Chalice.

Utopia Sprawl

Enchant Forest
As Utopia Sprawl enters, choose a color.
Whenever enchanted Forest is tapped for mana, its controller adds an additional one mana of the chosen color.