Glimpse the Impossible

Exile the top three cards of your library. You may play those cards this turn. At the beginning of the next end step, if any of those cards remain exiled, put them into your graveyard, then create a 0/1 colorless Eldrazi Spawn creature token for each card put into your graveyard this way. Those tokens have "Sacrifice this creature: Add {C}."

Mountain

Cabal Ritual

Add {B}{B}{B}.
Threshold — Add {B}{B}{B}{B}{B} instead if seven or more cards are in your graveyard.

Wooded Ridgeline

({T}: Add {R} or {G}.)
Wooded Ridgeline enters tapped.

Reckless Impulse

Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Wrenn's Resolve

Night's Whisper

Geothermal Bog

({T}: Add {B} or {R}.)
Geothermal Bog enters tapped.

Guttersnipe

Whenever you cast an instant or sorcery spell, Guttersnipe deals 2 damage to each opponent.

Thriving Bluff

Thriving Bluff enters tapped. As it enters, choose a color other than red.
{T}: Add {R} or one mana of the chosen color.

Goblin Anarchomancer

Each spell you cast that's red or green costs {1} less to cast.

Dark Ritual

Molten Tributary

({T}: Add {U} or {R}.)
Molten Tributary enters tapped.

Desperate Ritual

Add {R}{R}{R}.
Splice onto Arcane {1}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Goblin Electromancer

Instant and sorcery spells you cast cost {1} less to cast.

Conduit Pylons

When Conduit Pylons enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
{T}: Add {C}.
{1}, {T}: Add one mana of any color.