msem-instigator

Raider's Den enters tapped.
{T}: Add {R}.
{R}, {T}: Target creature you control gains menace until end of turn. Activate only as a sorcery and only if you control a red creature.

({T}: Add {G} or {U}.)
Rainforest Spring enters tapped.

({T}: Add {W} or {U}.)
Rainsculpted Gorge enters tapped.
{1}, {T}: Add {W}{W} or {U}{U}.

Raintouched Basin enters tapped.
{T}: Add {U}.
Desertcycling {1}{U} ({1}{U}, Discard this card: Search your library for a Desert card, reveal it, and put it into your hand, then shuffle.)

Ralora, Unforgiving Depths enters tapped.
Whenever a source deals damage to you, put a creation counter on Ralora.
{T}, Remove ten creation counters from Ralora and sacrifice it: It deals 10 damage to target player or planeswalker.

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

Ravaged Monument enters tapped.
{T}: Add {G}.
{2/G}{2/G}: Ravaged Monument becomes a 4/4 green Elemental creature until end of turn. It's still a land.

Ravenous Hollow enters tapped.
{T}: Add {B} or {R}.
{2}{B}{R}: Until end of turn, Ravenous Hollow becomes a Wolf creature with first strike in addition to its other types.
Scavenge {2}{B}{R}

{T}: Add {C}.
{2}, {T}: Target creature gains haste until end of turn.

Flying

{T}: Add {C}.
{1}, {T}: Add one mana of any color. This ability costs {1} less to activate if there are three or more colors among cards in your graveyard.

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

Reclusive Copse enters 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}

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.

Whenever a creature enters, each opponent loses 1 life.

{T}, Sacrifice Renewal Grove: Search your library for a basic land card, put it onto the battlefield, then shuffle. If Renewal Grove entered 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 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.”)

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

At the beginning of your end step, put a creature card that's exiled with this enchantment onto the battlefield under your control. That creature becomes a 1/1 Spirit creature in addition to its other types and gains flying and “If this creature would die, put it on the bottom of its owner's library instead.”

Restored Automaton enters with X +1/+1 counters on it.
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)

(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.