msem-instigator

Once each turn, when Groz, the Nightshaper enters or you attack with one or more Horrors, you may return target nonlegendary creature card from your graveyard to your hand. Then if Groz isn't a token, create a token that's a copy of that creature card.
{2}{B}{B}, Discard Groz: Create a token that's a copy of Groz, the Nightshaper, except it's 4/4 and isn't legendary. Activate only as a sorcery.

As an additional cost to cast this spell, sacrifice an artifact or creature.
Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Colossal 2—{6}{U} (You may cast this for its colossal cost to have it enter with two +1/+1 counters; or pay {6}{U} as a sorcery: Put two +1/+1 counters on it if it has none.)
When Titanic Fathomclaw's colossal ability puts one or more counters on it, return target instant or sorcery card from your graveyard to your hand.

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

Look at target player's hand. You may choose a nonland card from it. If you do, that player reveals that card, puts it on the bottom of their library, then draws a card.

Draw a card. If this spell was foretold, instead surveil 2, then draw two cards.
Foretell {2}{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.)

Return target creature to its owner's hand. If you controlled that creature, draw a card.

Enchant creature
Enchanted creature blocks each combat if able.
Whenever enchanted creature attacks, it loses flying until end of turn.

Lionize {U}{R}{W} ({U}{R}{W}, Exile this card from your hand: Put a +1/+1 counter on target creature and it gains the following ability until end of turn. You may cast this card on a later turn from exile.)
Whenever this creature deals combat damage to a player or noncreature permanent, return target noncreature card from your graveyard to your hand.

Haste
Whenever Herald of the Humble deals combat damage to a player, that player reveals the top card of their library. If it's a nonland card with mana value 3 or less, they may cast it without paying its mana cost.

Each player draws two cards.
Flashback—{W}, Tap two untapped white creatures you control. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Paranoia—Exile a creature card from your graveyard. (You may cast this spell for its paranoia cost when a permanent you control leaves the battlefield.)
Equipped creature gets +2/+0.
Equip {1}

When Ancient of the Glade enters, put a +1/+1 counter on each other creature you control.
{2}, Remove a +1/+1 counter from a creature you control: That creature gains indestructible until end of turn.

Whenever a creature you control is dealt damage, it gains indestructible until end of turn. (If it survives.)

Flash
Flying
When Champion of the Provinces enters, return any number of other permanents you control to their owner's hands.

Exile a nonland card from target opponent's graveyard. Copy it. You may cast the copy without paying its mana cost. (Copies of permanents enter as tokens.)

Whenever you cast a Knight spell or an Adventure spell, Wimbledon's Squire gets +1/+1 until end of turn.

Whenever you cast your second spell each turn, Expressive Performer deals 1 damage to each opponent.
{3}{R}, {T}, Exert Expressive Performer: It deals 2 damage to each player. (An exerted creature won't untap during your next untap step.)

Counter target nonenchantment spell.

Exile target nonland permanent.

Counter target spell if you have more cards in hand than its controller.

At the beginning of each end step, put a +1/+1 on Quickstep Ranger for each +1/+1
counter you've put on creatures under your control this turn.
Surpass {5}{G} ({5}{G}: Transform this creature. This costs {1} less to activate for each counter
on it. Activate only as a sorcery.)

Unending Slime enters with X +1/+1 counters on it.
{2}{G}{G}{G}: Return Unending Slime from your graveyard to your hand.

Return up to two target instant and/or sorcery cards from your graveyard to your hand. Exile Intense Revelation.

({T}: Add {R} or {W}.)
Cloudsteel Summit enters tapped.
{1}, {T}: Add {R}{R} or {W}{W}.