msem-instigator

{T}: Add one mana of any color. Spend this mana only to cast a creature spell or activate an ability of a creature.
{5}{W}{U}{B}{R}{G}, Sacrifice Osk, the Maker's Pet: Create Osk Awakened, a legendary 20/20 green Squirrel God creature token with hexproof, trample, and indestructible.

Whenever Ujuraq, Elder Watcher enters the battlefield or attacks, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
Ujuraq gets +3/+3 and has trample as long as there are eight or more cards in your graveyard.

Flash
Return another artifact, creature, or enchantment you control to its owner's hand: Caylin Whirlwind gets +3/+3 until end of turn. Activate only once each turn.

Noncreature spells your opponents cast cost {1} more to cast for each counter on Judges of Bearidge.
{5}{W}{U}: Put a +1/+1 counter on Judges of Bearidge, then detain each creature with lesser power.

Prowess
Whenever Unseen Hand attacks, exile target noncreature, nonland card with mana value 1 or less from your graveyard. Copy that card. You may cast the copy. (You still pay its costs.)

{U}{B}, {T}: Draw a card, then each player exiles the top card of their library. Then if a player owns two or more cards exiled with Arina, Volarian Explorer, exile her, then return her to the battlefield transformed under her owner's control.

[+1]: Tap up to one target creature. It doesn't untap during its controller's next untap step.
[–2]: Exile target card from a graveyard. Create a 2/2 blue and black Elemental creature token.
[–7]: You get an emblem with “You may play cards from exile.”

Flash
Flying
Whenever a player discards a card, you draw a card. This ability triggers only once each turn.

Whenever Search the Shadows or a nontoken Ninja or Rogue enters the battlefield under your control, create a 1/1 blue Ninja creature token with “This creature can't be blocked.”
Whenever one or more Ninja and/or Rogue creatures you control deal combat damage to a player, draw a card.

Deathtouch, protection from legendary
Vielle, Undercity Wayfarer has all loyalty abilities of permanents on the battlefield that cost +1, +0, or -1. (Before cost changes. Add or remove loyalty counters from Vielle to pay their loyalty costs.)

Glorious end — When Toros the Warchief dies, if it was tapped, return it to the battlefield at the beginning of the next end step.
Attacking creatures you control have deathtouch.

Whenever a land enters the battlefield under your control, create a 1/1 red Elemental creature token. Then if you control three or more Elementals, exile Aleryn, Trapseeker, then return him to the battlefield transformed under his owner's control.

[+1]: Whenever a creature you control attacks this turn, Aleryn, Dungeon Disabler deals 1 damage to the defending player.
[–1]: Add X mana in any combination of {R} and/or {G}, where X is the number of creatures you control.
[–6]: You get an emblem with “Whenever a player casts a spell, this emblem deals 3 damage to any target.”

Artifacts you control have “{T}: Add one mana of any color.”
{2}{R}{G}: Create a 3/2 green Crocodile creature token with trample. It gains haste until end of turn.

Choose one —
• You may sacrifice a creature. When you do, it deals damage equal to its power to any target.
• Target creature gets +4/+4 and gains trample until end of turn.
• Destroy target artifact.

This spell costs {1} less to cast for each legendary creature you control.
Search your library for a legendary creature card with mana value X or less, put that card onto the battlefield, then shuffle.

This spell can't be countered.
Vigilance
Noncreature spells cost {1} more to cast.

Flash
When Kimar, Lightforger enters the battlefield, she deals damage equal to her power to each attacking creature.
At end of combat, if three or more creatures died this turn, exile Kimar, then return her to the battlefield transformed under her owner's control.

[+1]: Choose up to one target creature. Until your next turn, whenever that creature attacks you or Kimar, Kimar deals 4 damage to that creature.
[–1]: Put a +1/+1 counter on target creature. That creature gains lifelink until end of turn.
[–7]: Search your library for a creature card and put it onto the battlefield. You gain life equal to its power. Then shuffle.

Vigilance
Creatures you control with power 1 or less can't be blocked by creatures with power 3 or greater.
Resilience (When this dies, exile it, then create a 1/1 token copy without resilience.)

Refine {3}{W}{B} (You may cast this spell by sacrificing an artifact and paying the refine cost reduced by that artifact's mana value.)
When H-9K Prototype enters the battlefield, if it was refined, destroy target nonland permanent.

Lifelink
{W}{B}, {T}, Discard a card: Look at the top three cards of your library. You may reveal an enchantment card from among them and put it into your hand. Put the rest on the bottom of your library in any order.
When you have no cards in hand, exile Revela, then return her to the battlefield transformed under her owner's control.

[+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.

This spell can't be countered.
Flying
Whenever Ajax, Tyrant of the Empire enters the battlefield or deals combat damage to a player, draw a card.
Whenever Ajax or another Dragon you control attacks, that Dragon deals 2 damage to any target.

Exile the top two cards of your library. Until your next end step, you may play those cards.
Breakthrough — Whenever you cast your third spell each turn, you may exile Devoted Artistry from your graveyard. If you do, you may cast a copy of it at the beginning of your next upkeep. (You still pay its costs.)