msem-instigator

Whenever a player casts a spell from their hand, they reveal the top card of their library. If it's a nonland card with a mana value less than that spell's, they may cast it without paying its mana cost. Otherwise, they put it on the bottom of their library.
{2}{U}: Scry 1.

Defender
Whenever Slumbering Bear is dealt damage, put a +1/+1 counter on it.
Remove a +1/+1 counter from Slumbering Bear: It can attack as though it didn't have defender this turn.

Whenever you cast a spell, sacrifice a permanent and draw a card.
Exile three cards from your graveyard: Counter target noncreature spell unless its controller pays {1}.

Prevent all combat damage that would be dealt this turn.
Draw a card.

As an additional cost to cast this spell, discard a card.
Search your library for a card with mana value X or less, where X is 1 plus the discarded card's mana value, reveal it, put it into your hand, then shuffle.

This spell costs {2} less to cast if a permanent you controlled left the battlefield this turn.
Target creature gets +3/+0 and gains trample until end of turn.

Hexproof
Whenever one or more cards are put into your graveyard from anywhere, Creeping Hidebehind gets +1/+0 until end of turn.

Hexproof
When Cantrip Collector enters, rediscover an instant card. (Look at the top card of your library. You may reveal it and put it into your hand if it's an instant card. Otherwise, put it back or into your graveyard.)

Whenever Savvy Saboteur attacks, target creature defending player controls can't block target creature you control this turn.

Whenever a storied permanent you control enters, each opponent loses 2 life. (Enchantments and legendary permanents are storied.)

Whenever a creature you control enters, if its mana value is greater than the number of bloom counters on From a Seed, put a bloom counter on From a Seed.
Creatures you control get +1/+1 for each bloom counter on From a Seed.

Reach
When Colonial Effigy dies, create a 1/1 white Spirit creature token with flying.

Vigilance, lifelink

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
When Cheerful Generator has three or more +1/+1 counters on it, remove them all and transform it.

Abyssal Crypt enters tapped.
{T}: Add {U} or {B}.
{2}{U}{B}, {T}, Sacrifice Abyssal Crypt: Draw a card.

{1}, {T}: Add one mana of any color.
Crew 1 (Tap any number of creatures you control with total power 1 or greater: This Vehicle becomes an artifact creature until end of turn.)

Search your library for a card and reveal it. If it has mana value X or less and this spell was foretold, you may play it without paying its mana cost. Otherwise, put it into your hand. Then shuffle.
Foretell {X}{B}{B} (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 New Alores Charmer attacks, you may tap target creature.

Search your library for a basic land card, reveal it, put it into your hand, then shuffle. You gain 2 life.

When Percy's Perfect World enters, search your library for a legendary white card, reveal it, put it into your hand, then shuffle.
If an effect would create one or more creature tokens under your control, it creates twice that many of those tokens instead.

Target creature you control gets +2/+2 until end of turn. It fights target creature with flying you don't control.

Deathtouch
When Kaneh Assassin enters, judge another target creature you control. (Honor it by putting a +1/+1 counter on it or condemn it by sacrificing it to draw a card.)

You have no maximum hand size.
{T}: Add {C}.
{3}, {T}: Create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever an experience ability puts a +1/+1 counter on a creature you control, put a +1/+1 counter on that creature.