msem-instigator

Lifelink
When Seeker of Lost Secrets leaves the battlefield, you may pay 2 life. If you do, search your library for a card, put that card into your hand, then shuffle.

Lifelink
Revelation spells you cast cost {1} less to cast.

Whenever you cast your second spell each turn, each opponent loses 1 life and you gain 1 life.

Primal {W} (During your turn, you may cast this spell for {W} instead of playing a land.)
Destroy target attacking or blocking creature.

Equipped creature has hexproof and distorted. (It can be blocked by tapped creatures but not untapped creatures.)
Equip {1}

When Seeker's Guardian enters, reveal the top card of your library.

Mill five cards, then you may exile any number of cards from your graveyard. Create an X/X black Horror creature token with menace, where X is the number of cards exiled in this way. (To mill five cards, put five cards from the top of your library into your graveyard.)

Flying
Whenever Seer of Clear Skies or another creature you control with flying attacks, that creature gets +1/+1 until end of turn.

Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{2}{W}: Create a 1/1 white Human Samurai creature token.

When Seikatsu Warleader enters, if it's not a token, create a token that's a copy of target creature token you control.

Deathtouch
Cards can't leave graveyards.
If a creature would die, you may pay {X}, where X is the number of cards in your graveyard. If you do, instead exile it, then return that card to the battlefield under your control.

When Seishin Rageshaper enters, create a 2/2 colorless Spirit creature token.
Colorless creatures you control have haste.

When Seishin Smokeshaper enters, create a 2/2 colorless Spirit creature token.
Whenever you cast a noncreature spell, colorless creatures you control get +1/+1 until end of turn.

When Seishin Tidekeeper enters, create a 2/2 colorless Spirit creature token.
Colorless creatures you control have flying.

Concord — This spell costs {4} less to cast if there are four or more card types among permanents you control.
Vigilance, trample, lifelink, haste

Return target permanent to its owner's hand. You may put a permanent card that shares a card type with it from your hand onto the battlefield.

Destroy target land. Add {R}{R}.

Seismic Strike deals damage to target creature equal to the number of Mountains you control.

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

Another target player reveals their hand. You may choose an instant or sorcery card from it and cast it without paying its mana cost.
Fuse (You may cast one or both halves of this card from your hand.)

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever a +1/+1 counter is put on Sejiri Skyhunter, it gains flying until end of turn.

Equipped creatures you control get +1/+1.
You may activate equip abilities any time you could cast an instant.
Equip {2}

Reveal the top five cards of your library. Put one of those cards into your hand. Target opponent chooses two of those cards. Exile the chosen cards, then put the rest into your hand.

At the beginning of your end step, for each opponent, destroy up to one target creature that player controls with power less than or equal to the amount of life that player lost this turn.
{3}{R}: Selezzar, Tyrant of Endak deals 2 damage to each opponent.

Enchant creature
When Selfish Epiphany enters, search your library for a card and put that card into your hand. Then shuffle.
Enchanted creature has indestructible and can't be sacrificed.