Scavenger Grounds

{T}: Add {C}.
{2}, {T}, Sacrifice a Desert: Exile all graveyards.

Seaside Citadel

This land enters tapped.
{T}: Add {G}, {W}, or {U}.

Secluded Steppe

This land enters tapped.
{T}: Add {W}.
Cycling {W} ({W}, Discard this card: Draw a card.)

Unshakable Tail

Clue

When this creature enters and at the beginning of your upkeep, surveil 1.
Whenever one or more creature cards are put into your graveyard from your library, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
{2}, Sacrifice a Clue: Return this card from your graveyard to your hand.

Selesnya Sanctuary

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {G}{W}.

Sheltered Thicket

({T}: Add {R} or {G}.)
This land enters tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

Shrine of the Forsaken Gods

{T}: Add {C}.
{T}: Add {C}{C}. Spend this mana only to cast colorless spells. Activate only if you control seven or more lands.

Simic Growth Chamber

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {G}{U}.

Skycloud Expanse

Slayers' Stronghold

{T}: Add {C}.
{R}{W}, {T}: Target creature gets +2/+0 and gains vigilance and haste until end of turn.

Spire of Industry

{T}: Add {C}.
{T}, Pay 1 life: Add one mana of any color. Activate only if you control an artifact.

Sungrass Prairie

Sunhome, Fortress of the Legion

{T}: Add {C}.
{2}{R}{W}, {T}: Target creature gains double strike until end of turn.

Sunken Hollow

({T}: Add {U} or {B}.)
This land enters tapped unless you control two or more basic lands.

Morska, Undersea Sleuth

You have no maximum hand size.
At the beginning of your upkeep, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Whenever you draw your second card each turn, put two +1/+1 counters on Morska.

Boltbender

A Mysterious Creature

Disguise {1}{R} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)
When this creature is turned face up, you may choose new targets for any number of other spells and/or abilities.

Murders at Karlov Manor Commander