msem-instigator

{T}, Sacrifice Decrepit Crags: Search your library for a Swamp or Mountain card and put it onto the battlefield tapped, then shuffle.

When Dedicated Waypoint enters, create a 1/1 white Scout creature token.
{T}: Add {R}, {W}, or {B}.

At the beginning of your upkeep, choose an opponent. That player creates a 3/2 colorless Horror creature token.
{2}: Target opponent gains control of Deepdrinker's Effigy.

Deeplife Cavern enters tapped unless you control a Forest.
{T}: Add {U} or {B}.

{T}: Add {C}.
{3}{R}: Until end of turn, Defect's Precinct becomes a 3/3 creature. It's still a land. It has trample if {G} was spent to activate this ability, has vigilance if {W} was spent, and has hexproof if {U} was spent.

Whenever you cast a spell, if it shared a color with the last spell you cast this turn, put two +1/+1 counters on Defected Android.

Flying

At the beginning of each player's end step, that player sacrifices a permanent.

As Den of Vice enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {U}, {B}, or {R}.

{4}{B}: Depthlight Beacon gets +1/+1 and gains lifelink until end of turn.
Cycling {2/B} ({2/B}, Discard this card: Draw a card.)

({T}: Add {R}.)
Derelict Amphitheatre enters tapped.
{R}, {T}, Reveal a red card from your hand: Scry 1.

{T}: Add one mana of any color.
When you tap Derelict Town for mana, return it to its owner's hand.

Defender
Whenever Derelict Watcher or another Scarecrow you control enters, create a 1/1 black Bird creature token with flying.

Descended Countryside enters tapped.
{T}: Add {G} or {W}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Descended Delta enters tapped.
{T}: Add {U} or {R}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Descended Fissure enters tapped.
{T}: Add {B} or {R}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Descended Glacier enters tapped.
{T}: Add {W} or {U}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Descended Gorge enters tapped.
{T}: Add {R} or {G}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Descended Hollow enters tapped.
{T}: Add {U} or {B}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Descended Marsh enters tapped.
{T}: Add {B} or {G}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Descended Meadow enters tapped.
{T}: Add {G} or {U}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Descended Mortuary enters tapped.
{T}: Add {W} or {B}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Descended Towers enters tapped.
{T}: Add {R} or {W}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Desert Temple enters tapped.
As Desert Temple enters, an opponent of your choice chooses Oasis or Desiccation.
• Oasis — {T}: Add one mana of any color.
• Desiccation — {T}: Add {C}{C}. You lose 1 life.

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast riddle spells.
{1}, {T}: Add one mana of any color.