msem-instigator

At the beginning of your upkeep, you may pay 2 life. If you do, exile the top card of target opponent's library. If a nonland card is exiled this way, copy it. You may cast the copy. (You still pay its costs, including color. Copies of permanents enter as tokens.)

Whenever Path Lighter deals combat damage to a player, it explores. (Reveal the top card of your library. Put it into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then you may put that card in your graveyard.)

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Griffin Skycaller enters, target creature you control gets +1/+1 and gains flying until end of turn.

When Wistful Fox enters, reveal the top eight cards of your library. You may put a creature card from among them into your hand. Put the rest on the bottom of your library in a random order.

Lifelink
When Adept of Transfusions enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
Tokens you control have “{1}, {T}, Discard a card, Sacrifice this token: Draw a card.”

Flying
Whenever an opponent discards one or more cards, fateseal 1. (To fateseal 1, look at the top card of an opponent's library, then you may put it on the bottom of that player's library.)

Equipped creature gets +2/+2.
Art of war — At the beginning of your end step, if equipped creature dealt damage to an opponent this turn, untap each equipped creature you control.
Equip {2}

When Lysene enters, you may search your library for a card with foretell, reveal it, put it into your hand, then shuffle. The next card you foretell this turn costs {0} to foretell.
Whenever you foretell a card or cast a foretold spell, Pirates and Rogues you control get +1/+0 until end of turn. Up to one target Pirate or Rogue you control can't be blocked this turn.

Riv's Safehouse enters tapped.
When Riv's Safehouse enters, you may mill two cards.
{T}: Add {U} or {B}.

Counter target spell if it has mana value 2 or less or if this spell was foretold.
Foretell {1}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Whenever Wadepool Frog attacks, it gains flying until end of turn.

When Rabudan Chiseler enters, you may search your library for an Aura or Equipment card, reveal it, put it into your hand, then shuffle.

Create a 1/1 white Soldier creature token with vigilance.
At the beginning of combat on your turn, you may pay {2}{W}. If you do, creatures you control get +1/+1 until end of turn.

Whenever you cast a spell, if you sacrificed permanents, discarded cards, and/or paid life as an additional cost to cast it, Kernel Knot deals 2 damage to any target. (Sacrificing permanents for mana doesn't count.)

Flying
Whenever Havengul Banshee attacks, each creature defending player controls gets -1/-0 until end of turn.
{3}{U}: Return Havengul Banshee from your graveyard to the battlefield transformed under your control attached to target opponent. Activate only as a sorcery.

Enchant player
When Curse of Grasping Air enters, enchanted player reveals their hand. You choose a nonland card from it. That player discards that card.
Spells you cast that target enchanted player cost {1} less to cast.

Target creature gets +1/+1 and gains double strike until end of turn. (That creature deals both first-strike and regular combat damage.)

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, each opponent loses life equal to Morose Harpist's power.

Whenever you cast a noncreature spell, you may put a progress counter on Sovereign Skies.
[PROGRESS 2+] Indestructible
{T}: Add {C}.
[PROGRESS 9+] Sovereign Skies is a 9/9 Ship artifact creature with flying.

Enchant opponent
Creatures enchanted player controls with power 2 or less can't block.

Each creature you control enters with an additional +1/+1 counter on it.
When Training Sim enters, create a Function token with “Target creature you control fights target creature you don't control.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Madness {4}{G}{G} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)
Look at the top eight cards of your library. You may reveal a creature card from among them and put it into your hand, then put the rest on the bottom of your library in a random order. Then if this spell was cast for its madness cost, you may put a creature card from your hand onto the battlefield.

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)

At the beginning of combat on your turn, target creature gets +1/+1 and gains haste until end of turn.