msem-instigator

Choose two —
• Return up to two target nonland permanents to their owner's hands.
• Any number of target players each sacrifice a creature.
• Any number of target players each sacrifice a planeswalker.
• Any number of target players each sacrifice an artifact or enchantment.

Flying
When Sahra's Harbinger enters, reveal the top six cards of an opponent's library and separate them into two piles. That opponent chooses one of those piles and puts it into their hand. You may cast any number of nonland cards in the other pile without paying their mana costs.

Trample, haste
When Sahra, the Consuming enters or attacks, sacrifice a permanent.
At the beginning of your end step, transform Sahra unless you've sacrificed two or more permanents this turn.

Flying
Saki of the Sea and Sky gets +1/+1 for each card inscribed onto it and each permanent attached to it.

[+2]: Exile the top two cards of your library. You may put a permanent card from among them into your hand.
[–3]: Create Salim, a legendary 3/3 green and white Cat creature token with vigilance, trample, and indestructible.
[–3]: You get an emblem with “Whenever a creature you control enters, that creature gets +2/+2 and gains haste until end of turn.”

{3}{W}: Return another target artifact or creature you control to its owner's hand.
{1}{B}: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

When this creature enters, each player discards a card. Then return an instant or sorcery card from your graveyard to your hand.

At the beginning of your upkeep, you gain 1 life for each color among permanents you control.
{W}{U}{B}{R}{G}, Sacrifice Sartha's Studies: Double your life total.

Flying, vigilance, lifelink
During each of your turns, you may cast a multicolored spell from your graveyard.

Other creatures you control that entered this turn have haste and lifelink.
{T}: You may put a creature card from your hand onto the battlefield.

{3}{B}: You mill two cards. Each opponent loses 2 life.
{1}{G}: You may put a land card from your hand or graveyard onto the battlefield tapped.

Savage Lands enters tapped.
{T}: Add {B}, {R}, or {G}.

({T}: Add {G}.)
Savage Sanctuary enters tapped with two sanctum counters on it.
{T}, Remove a sanctum counter from Savage Sanctuary: Add {R} or {W}.

Whenever Scarhide, Arsenal Crafter attacks, create a token that's a copy of an Equipment attached to Scarhide and attach the token to Scarhide. When you can't, arm it. (Create a colorless Equipment artifact token with “Equipped creature gets +1/+0” and equip {2}, then attach it to that creature.)

Search your library for an enchantment card, reveal it, put it into your hand, then shuffle.

Seaside Citadel enters tapped.
{T}: Add {G}, {W}, or {U}.

Augmented — At the beginning of combat on your turn, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on Second Wave Explorer.

{T}, Sacrifice a creature: When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.

Whenever you play a land, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
{1}{G}{U}{R}, Sacrifice three Clues: Exile cards from the top of your library until you exile three nonland cards. You may cast any number of those cards without paying their mana costs.

When Seeker of Far-Off Lands enters, search target opponent's library for a land card, put it onto the battlefield tapped under your control, then that player shuffles.

When Seeker of Horizons enters, reveal the top three cards of your library. You may put a permanent card from among them into your hand. Put the rest on the bottom of your library in any order.
Recite {1}{U} (You may cast this creature from your graveyard for its recite cost. If you do, exile it when it enters or if it would leave the battlefield.)

For any number of permanent types, you may exchange control of two target permanents that share that type.

Soldiercycling {1}{W}, Wizardcycling {1}{U}, Zombiecycling {1}{B}, Warriorcycling {1}{R}, Elfcycling {1}{G} ({1}{G}, Discard this card: Search your library for an Elf card, reveal it, and put it into your hand, then shuffle.)
Sentinel of Latter Days is every creature type as long as it's in your library.

Menace
When Setar Ritualist enters or whenever you cast a spell, if {U}{R} was spent to cast it, Setar Ritualist deals 3 damage to target permanent, then tap that permanent. Put a +1/+1 counter on Setar Ritualist.

{U}{R}{W}, Discard a card named Sha'Iv, God of Order: Sha'Iv gains indestructible and becomes a God creature in addition to its other types.
Whenever Sha'Iv enters or attacks, choose target creature an opponent controls. Untap it, then tap each other creature that player controls. They don't untap during their controller's next untap step.