msem-instigator

As Reborn Altar enters the battlefield, you may pay 3 life. If you don't, it enters the battlefield tapped.
{T}: Add {R}, {W}, or {B}.

Reclusive Copse enters the battlefield tapped.
{T}: Add {B} or {G}.
{1}{B}{G}: Until end of turn, Reclusive Copse becomes an Insect creature with deathtouch in addition to its other types.
Scavenge {B}{G}

Menace
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)

When Recon Drone enters the battlefield, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle. Then if you did, put a card from your hand on the bottom of your library.

Flash
{1}, {T}: Scry 1.

Whenever you draw a card, put a hatch counter on Reefcrown Egg.
{T}, Sacrifice Reefcrown Egg: You may put a creature card with mana value less than or equal to the number of hatch counters on Reefcrown Egg from your hand onto the battlefield.
Cycling {2} ({2}, Discard this card: Draw a card.)

Whenever a creature dealt damage by Rei's Betrayer this turn dies, you gain life equal to that creature's toughness.

Rei, the Supplanter gets +1/+1 for each Forest you control.
At the beginning of each player's end step, if that player didn't play a land this turn, create a Forest token.

[+1]: Create a 1/1 blue Elemental creature token with flying, then crystallize twice. (Put a +1/+1 counter on a creature you control or create a Treasure.)
[–3]: Exile target nonland permanent. As long as it's exiled, its owner may pay {W}{U}{B}{R}{G} as a sorcery to put it into their hand.
[–7]: You get an emblem with “Pay 1 life: Add one mana of any color.” Then you gain 100 life.

When Remnant of Lost Times enters the battlefield, scry 1.
{2}, Sacrifice Remnant of Lost Times: Draw a card.

{T}: Target player exiles a card from their graveyard.
{2}, Sacrifice Remnant of Past Realities: Exile each opponent's graveyard. Draw a card.

Whenever a creature enters the battlefield, each opponent loses 1 life.

When Renegade Servitor enters the battlefield, you gain 2 life and scry 1.

{T}, Sacrifice Renewal Grove: Search your library for a basic land card, put it onto the battlefield, then shuffle. If Renewal Grove entered the battlefield since your last upkeep, that land doesn't untap during your next untap step.

Whenever a creature dies, put a +1/+1 counter on Repository of Thoughts.
At the beginning of each combat, you may move a counter from Repository of Thoughts to target creature.

Repurposed Construct enters the battlefield tapped.
{T}: Add {B} or {G}.
{B}{G}, {T}, Sacrifice Repurposed Construct: Conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

When Repurposed Custodian enters the battlefield, shuffle any number of target cards from graveyards into their owner's libraries.

({T}: Add {G} or {W}.)
Whenever Resplendent Substratum becomes tapped, you lose 1 life unless you control two or more basic lands.

(Transforms from Ruined Theater.)
{T}: Add one mana of any color.

{T}: Add {C}.
{3}, Exile Resurgent Oasis from your graveyard: Choose a basic land type. Create a tapped colorless land token that's a Desert and the chosen basic land type.

[+2]: Each player sacrifices a creature. Then each player who did creates a 1/1 white and black Spirit enchantment creature token.
[–X]: You may put an enchantment card with mana value X or less from your hand onto the battlefield.
[–6]: Shuffle, then reveal the top seven cards of your library. Put any number of enchantment cards from among them onto the battlefield. Shuffle the rest into your library.

Archive 3 (As this enters, shuffle the top three cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever you draw a card from the archived library, put the top card of your main library on the bottom of the archived library.
{U}: Exchange a card from the archived library with a card from your hand.

Whenever you cast an instant or sorcery spell, put a loyalty counter on Reytali of Endless Muses.
[0]: Add X mana in any combination of colors, where X is the number of spells you've cast this turn.
[–3]: Create two 3/1 red Sand creature tokens with haste.

Rice Fields enters the battlefield tapped.
{T}: Add {W} or {U}.
When Rice Fields enters the battlefield, you may put a loyalty counter on a planeswalker you control.

{T}, Sacrifice Rickety Guildhall: Search your library for a Forest or Island card and put it onto the battlefield tapped, then shuffle.