msem-instigator

Creatures you don't control get -1/-1.
Mirage {1}{B} (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.)

Target creature gets -3/-2 until end of turn.

As Aquatic Refuge enters, you may tap an untapped creature you control. If you don't, Aquatic Refuge enters tapped.
{T}: Add {W} or {U}.

{U}: Aqueous Treader gets +1/-1 until end of turn.
{U}: Aqueous Treader gets -1/+1 until end of turn.

Target creature you control deals damage equal to its power to target creature you don't control.

Flying
When Arbiter of Silence enters, exile all other creatures until Arbiter of Silence leaves the battlefield. (They return to the battlefield under their owners' control.)

Enchant creature
Enchanted creature gets +1/+1 and has flying and prowess.

{U}, Exile an instant or sorcery card from your graveyard: Draw a card, then discard a card.
{R}, Exile an instant or sorcery card from your graveyard: Arcane Harvesters deals 1 damage to any target.

Whenever you cast an instant or sorcery spell, you may pay {1}. If you do, choose one—
• Draw a card, then discard a card.
• Tap target creature.
• Target creature gains flying until end of turn.
• Target player mills two cards.

Counter target spell. If that spell is countered this way, until the end of your next turn the next spell you cast that shares a type with it costs {X} less to cast, where X is the countered spell's mana value.

{T}: Add one mana of any color in your commander's color identity.

Counter target spell unless its controller pays {2}.
Reprise {3}{U} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

When Arcanomancer enters, return up to one target instant card and up to one target sorcery card from your graveyard to your hand.

When Archaeomancer enters, return target instant or sorcery card from your graveyard to your hand.

Whenever Archlegislator attacks, adjudicate. (Create a white Aura enchantment token with enchant creature and “Sacrifice this token: Untap enchanted creature” attached to target creature.)
{3}{R}{R}, {T}, Sacrifice an Aura: Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.

Exile up to three target creatures you control, then return those cards to the battlefield under your control tapped.

Attacking creatures you control get +1/+0 until end of turn.
Draw a card.

Kicker {1}{R} (You may pay an additional {1}{R} as you cast this spell.)
Attacking creatures get +2/+0 until end of turn. Those creatures also gain first strike until end of turn if this spell was kicked.

If a creature would leave the battlefield this turn, exile it instead.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, target player sacrifices a creature.

[+1]: Tap up to one target creature. It doesn't untap during its controller's next untap step.
[–2]: Exile target card from a graveyard. Create a 2/2 blue and black Elemental creature token.
[–7]: You get an emblem with “You may play cards from exile.”

{U}{B}, {T}: Draw a card, then each player exiles the top card of their library. Then if a player owns two or more cards exiled with Arina, Volarian Explorer, exile her, then return her to the battlefield transformed under her owner's control.

When Arisen Haploc enters, return target creature card from a graveyard to its owner's hand.
Revive {5}{B}{B} ({5}{B}{B}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Target creature gains double strike until end of turn.

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature gets +2/+2.
{1}{G}: Regenerate enchanted creature.