msem-instigator

At the beginning of each opponent's end step, that player gets a poison counter unless damage was dealt this turn.

When Forlorned Knight enters, you may sacrifice another creature. If you do, create two 1/1 white Human creature tokens.
Whenever you attack, if another creature died under your control this turn, creatures you control get +1/+1 until end of turn.
Fleeting {W}{B} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

Target creature gets -1/-1 until end of turn. Germinate. (Put a +1/+1 counter on a creature or create a 1/1 green Saproling creature token.)

Flying
Synchronous Hellkite enters with a +1/+1 counter for each other artifact you control.
Sacrifice three artifacts: Return Synchronous Hellkite from your graveyard to the battlefield.

Whenever Lightseeker Nymph perseveres, search your library for a basic land card, put it onto the battlefield tapped, then shuffle. (A creature perseveres when it survives damage.)

Whenever The Dreamer enters or you play a card exiled with them, exile the top two cards of your library face down, then another face up.
You may play face up cards exiled with The Dreamer.
{T}, Sacrifice The Dreamer: Look at each face down card exiled with The Dreamer. You may cast one without paying its mana cost.

Whenever Breakneck Barque becomes blocked by a creature, Breakneck Barque deals 3 damage to that creature.
Crew 3 (Tap any number of creatures you control with total power 3 or greater: This Vehicle becomes an artifact creature until end of turn.)

Target player loses 1 life. Scry 1.
Fabled {2}{B} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that player.)

Draw three cards, then reveal your hand.

Prowess
When Grasper of Secrets enters, choose one —
• Return target creature to its owner's hand.
• Return target instant or sorcery card from your graveyard to your hand.
Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Flying
Other creatures you control with flying get +1/+1.

Enchant creature
Enchanted creature gets +1/+1 and has flying and prowess.

Magma Spray deals 2 damage to target creature. If that creature would die this turn, exile it instead.

Whenever a creature you control enters for the second time each turn, you may put a +1/+1 counter on Warren Wardens.

Concord — This spell costs {2} less to cast if there are four or more card types among permanents you control.
Vigilance (Attacking doesn't cause this creature to tap.)

When Dwarven Tunnelers enters, create a tapped Treasure token.
{T}: Target creature with power 2 or less can't be blocked this turn.

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.
{B}: Exchange a card from the archived library with a card from your hand.

({T}: Add {U}.)
Wanderlust — Otherworldly Island enters tapped unless you control four or more other differently named lands.
{1}, {T}: Add one mana of any color.

When Wayfaring Realmstitcher enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

({T}: Add {G}.)
Seedshrine enters tapped.
When Seedshrine enters, you may put a +1/+1 counter on target creature.

[+1]: Discard a card. If you did, draw a card.
[–2]: Create a Bullet token. Until end of turn, if a Bullet you control would deal damage, it deals that much damage plus 1 instead. (It’s an artifact with “{T}, Sacrifice this artifact: It deals 1 damage to any target.”)

Archive 5 (As this enters, shuffle the top five cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
You may play lands from the archived library.

When Stoic Observation enters, mill two cards, then you may return a creature card from your graveyard to your hand.
{3}{G}, Exile a creature card from your graveyard: Create a 2/2 green Wolf creature token. You gain 2 life.

Vigilance
Creature spells you cast cost {2} less to cast.
Other creatures you control can't attack or block.

Flying, haste
When Tech Chaser enters, exile the top three cards of target opponent's library.
Whenever Tech Chaser deals combat damage to an opponent, you may cast a card exiled with it, and you may spend mana as though it were mana of any color to cast it.