Mountain

Rewind

Counter target spell. Untap up to four lands.

Food Chain

Exile a creature you control: Add X mana of any one color, where X is 1 plus the exiled creature's mana value. Spend this mana only to cast creature spells.

Voidslime

Counter target spell, activated ability, or triggered ability. (Mana abilities can't be targeted.)

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

The First Sliver

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Sliver spells you cast have cascade.

Concealed Courtyard

This land enters tapped unless you control two or fewer other lands.
{T}: Add {W} or {B}.

Spirebluff Canal

This land enters tapped unless you control two or fewer other lands.
{T}: Add {U} or {R}.

Blooming Marsh

This land enters tapped unless you control two or fewer other lands.
{T}: Add {B} or {G}.

Inspiring Vantage

This land enters tapped unless you control two or fewer other lands.
{T}: Add {R} or {W}.

Botanical Sanctum

This land enters tapped unless you control two or fewer other lands.
{T}: Add {G} or {U}.

Secret Lair Drop