msem-instigator

({T}: Add {B} or {G}.)
Somber Marsh enters tapped.

Gain control of target creature with power 2 or less until end of turn. Untap that creature. It gains haste until end of turn.

At the beginning of your upkeep, if you control three or more creatures, you draw a card and you lose 1 life.
{2}{B}{G}: Create a tapped 1/1 Horror creature token that's all colors.

Deathtouch

{T}: Add {C}.
{1}{R}, {T}, Discard a card: Exile the top card of your library. You may play it until the end of your next turn.
At the beginning of combat on your turn, if there are eight or more nonland cards in your graveyard, you may pay {2}{R}{R} and exile this land. When you do, it deals 5 damage to any target.

Hexproof
As long as an opponent controls a permanent you own, Vault Sentinel gets +4/+4.

Flying, haste

Choose two or four —
• Each opponent sacrifices an artifact.
• Create a 1/1 red Warrior creature token.
• Creatures you control get +1/+0 and gain trample and haste until end of turn.
• Conjure a card named Fatigue and put it on top of your library. (It's a colorless sorcery that costs {2} with “Draw a card.”)

Eureka! (At the beginning of each end step, you get a research counter if you cast a spell this turn. Then if you have eight or more research counters, remove them and create a Masterpiece token of your choice.)
When Bottled Lightning enters, it deals 3 damage to any target. Scry 1.

[+1]: Untap target land.
[–1]: Exile the top card of your library. You may play that card until end of turn. If a land card is exiled this way, you gain 2 life.
[–7]: Untap each land you control. Lands you control become 3/3 Elemental creatures with haste until end of turn. They're still lands.

Flash
When Pyramid Lord enters, copy target instant or sorcery spell. You may choose new targets for the copy.
Mirage {1}{R}{R} (You may cast this spell for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Codex — Little Pig; Charging Cassowary; The Lonely Hunter; Shadowlurk; Blood Constrictor. (As this enters, conjure its contents into a shuffled face-up additional library.)
You may cast Adventures of this codex's contents from your graveyard.

Target creature gets +3/+3 until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Heroic — Whenever you cast a spell that targets Setessan Avenger, create a 1/1 green Nymph Dryad enchantment creature token with “{T}: Add {G}.”
Whenever Setessan Avenger deals combat damage to a player, untap all lands and Dryads you control.

When Hall of Remembrance enters, create two 1/1 white Spirit creature tokens with flying.
Whenever a Spirit you control enters, you gain 1 life.

Whenever a land you control enters, amass Soldiers 1. If that land is a Satrapy, amass Soldiers 2 instead. (To amass Soldiers 2, put two +1/+1 counters on an Army you control. It's also a Soldier. If you don't control one, create a 0/0 black Soldier Army creature token first.)

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.)

Whenever you cast a noncreature spell, you may put a progress counter on Reckless Research.
[progress 2+] At the beginning of your end step, mill two cards.
[progress 7+] At the beginning of your upkeep, choose target instant or sorcery card in your graveyard. You may cast it from your graveyard this turn.
At the beginning of your upkeep, choose target instant or sorcery card in your graveyard. You may cast it from your graveyard this turn.

Flying
Whenever Keeper of Twisted Light attacks, you gain 3 life.

Return target creature card from your graveyard to your hand. (Then exile this card. You may cast the creature later from exile.)

When The Lonely Prophet enters, exile a card you own from outside the game face down.
Whenever The Lonely Prophet deals combat damage, put the exiled card into your hand.

When Spinegraft Disabler enters, exile target creature until Spinegraft Disabler leaves the battlefield.

Motivate 3 (When this creature enters, you may motivate target creature with lesser power than this by putting three +1/+1 counters on it.)
At the beginning of combat on your turn, you may have target creature you control gain vigilance until end of turn.

{T}: Add {C}.
{3}: Living Planet becomes a 2/2 Elemental creature until end of turn. This ability costs {1} less to activate for each creature you control.