msem-instigator

Enchant creature
Enchanted creature can't attack or block, and its activated abilities can't be activated.
Mirage {W/U} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Whenever a nontoken creature you control dies, you may pay that creature's mana cost. If you do, search your library for a card and put it into your hand, then shuffle.

When Ramzi, Traveling Merchant enters, adjudicate land. (Create a white enchantment Aura token with enchant land and “Sacrifice this token: Untap enchanted land.” attached to target land.)
Whenever an Aura becomes attached to a land you control, create a 1/1 green Antelope creature token.

Sacrifice a creature. When you do, draw two cards. (Then exile this card. You may cast the creature later from exile.)

Exile target nonland permanent.

{T}: Until end of turn, target land is every basic land type in addition to its other types and its name becomes Morphic Sea.

Other Knights and Soldiers you control get +1/+0.
Cowards can't block Knights and Soldiers you control.
When Belmord Bloodcurdler enters, target creature an opponent controls becomes a Coward in addition to its other types. (This effect last indefinitely.)

Trample, ward {1}
Whenever Stardust Surveyor deals combat damage to a player, you may mill cards until you mill a creature card. When you do, return target creature card from your graveyard to your hand.

When Leery Sortie enters, create two 1/1 green Scout creature tokens.
{R}, Sacrifice Leery Sortie: Target creature can't block this turn.

{T}, Pay 1 life: Add {U} or {B}.
{2}, {T}, Sacrifice Weathered Wharf and another permanent: Draw a card. Activate only during your turn.

{T}: Add {R}.
Whenever you cast a spell from anywhere other than your hand, copy that spell. You may choose new targets for the copy.

Flying

Flying, ward {2}
The first noncreature spell you cast each turn costs {X} less to cast, where X is your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

As a spell you control is countered by a spell or ability an opponent controls while you control a Mountain, you may reveal Confront the Riddlemaster from your hand. When you do, cast it without paying its mana cost.
This spell can't be countered.
Confront the Riddlemaster deals 4 damage to any target.

Goblin Exploration Team gets +1/+0 for each non-Mountain land you control.

Creature spells you cast cost {1} less to cast.

Return up to one target creature to its owner's hand. If you do, that player discards a card at random.
Coalesce {5}{U}{B} (You may cast this from your graveyard for {5}{U}{B}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Whenever Shroud the World in Doom deals combat damage to an opponent, that player discards a card at random.

Menace, haste
As long as Arleigh, Spellblade Prodigy is tapped, the first spell you cast during each other player's turn costs {U/R} less to cast. This effect reduces only the amount of colored mana you pay. (For example, if you cast a spell with mana cost {1}{R}, it costs {1} to cast.)

{2}, Sacrifice Wicked Fossil: Target player loses 2 life and you gain 2 life.
{2}{B}{B}: Return Wicked Fossil from your graveyard to the battlefield transformed. Activate only during your turn.

Whenever you draw your second card each turn, other creatures you control get +1/+1 and gain indestructible until end of turn.

Target player discards a card. Until your next turn, whenever that player casts a spell, they discard a card.

Choose a nonland card name. Search target player's graveyard, hand, and library for any number of cards with that name and exile them. That player shuffles. For each card exiled from their hand this way, you discard a card.

Trample
Heretic (Whenever you cast a spell that doesn't share a color with this creature, it gets +1/+1 until end of turn.)

Flying
Venerable Skyblade can't attack unless defending player controls a creature with flying.
When Venerable Skyblade enters, you may put a +1/+1 counter on target creature you control.

Flying
At the beginning of each combat, target opponent may give themselves a poison counter. If they don't, Tower of Sorrows gets +3/+0 until end of turn.