msem-instigator

When Keeper of Blue Incense enters, submerge target card from your graveyard. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

Prowess
Whenever you cast a noncreature spell, noncreature spells you cast cost {1} less to cast until end of turn.

Whenever Mei's Student deals combat damage to a player, fateseal 1, then scry 1. (Look at the top card of an opponent's library, then you may put it on the bottom.)

Flying
When Midnight Visitor enters, you may return target creature to its owner's hand.

Prowess

Whenever you discard a card, tap up to one target creature.

Flash
Whenever you cast an artifact or enchantment spell, put a +1/+1 counter on Observer of Secret Paths. It can't be blocked this turn.

Colossal 3—{5}{U} (You may cast this for its colossal cost to have it enter with three +1/+1 counters; or pay {5}{U} as a sorcery: Put three +1/+1 counters on it if it has none.)
When Omendiver's colossal ability puts one or more counters on it, scry 3.

Primal {1}{G}{G} (During your turn, you may cast this spell for {1}{G}{G} instead of playing a land.)
When Orria's Ward enters, if you played a land this turn, draw a card. Otherwise, put two +1/+1 counters on it.

Deception {2}{U} ({2}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
When Oshiruko Silencer enters, return target creature to its owner's hand.

Whenever you create one or more tokens, scry 1.
{3}{U}, Sacrifice Pathshaper Mage: Aetherize target creature you control. Activate only as a sorcery. (To aetherize, create a token that's a copy of it, then exile that token.)

When Plane-Traversal Guide enters, you may exile a card you own from outside the game. When Plane-Traversal Guide is no longer on the battlefield, put the exiled card into your hand.

Flying
When Qi-Long Rainbringer enters, return up to one other target creature to its owner's hand.

When Quandary Seer enters, target player mills three cards. You shuffle up to three cards from your graveyard into your library.

Art of war — At the beginning of your end step, if Raiun Bay Scourge dealt damage to an opponent this turn, gain control of target artifact or enchantment until Raiun Bay Scourge leaves the battlefield.

Deception {U} ({U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever a Pirate or Rogue you control deals combat damage to a player, rediscover a Pirate or Rogue card. (Look at the top card of your library. You may reveal it and put it into your hand if it's a Pirate or Rogue. Otherwise, put it back or into your graveyard.)

When Recursion Runner enters, create a Function token with “If this spell isn't a copy, copy it. You may choose new targets for the copy.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Flying
Whenever you cast an artifact or enchantment spell, tap target artifact or creature an opponent controls. It doesn't untap during its controller's next untap step.

Serene Hart can't be blocked by creatures with power 4 or greater.

(Transcend as a sorcery to gain that type and a +1/+1 counter.)
Ward {2}
{2}{U}: Demigod — Exchange a card in your hand and a noncreature, nonland card in your graveyard.
{6}{U}: God — Exchange control of two target permanents that share a card type.

Flash
Whenever you cast Siflir, Elder Pawn or another spell, if you paid an alternate or additional cost to cast it, draw a card.
Wander {3}{U}{U} (You may cast this from the battlefield for its wander cost.)

Flash
You may cast cryptic spells as though they had flash. (Artifacts, enchantments, and modal spells are cryptic.)

When Silvercrest Historian enters, scry 1, then investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Flying
Whenever Skhorvall Patrol deals combat damage to a player, look at the top card of that player's library.

Ward {2}
Slippery Bunyip can't be blocked except by creatures with Adventures.