msem-instigator

Arcane Oasis enters tapped unless you control another Desert.
{T}: Add {U} or {R}.

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.

Counter target spell.
Look at the top three cards of your library. Put one on top and the rest on the bottom in any order.

Arcane Sanctum enters tapped.
{T}: Add {W}, {U}, or {B}.

Harmony — Attach Arcane Saxophone to target creature.
When Arcane Saxophone enters, harmonize. (Trigger up to one harmony of one permanent you control.)
Equipped creature gets +2/+2.
Equip {4}

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

Whenever you cast a spell, draw a card if that spell has the same name as a card in your graveyard.

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.)

If you casting a noncreature spell causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
Cycling {2} ({2}, Discard this card: Draw a card.)

Until end of turn, creatures you control get +1/+1 and gain prowess. If there are two or more instant and/or sorcery cards in your graveyard, draw a card.

Equipped creature gets +1/+0.
Whenever equipped creature attacks, you may draw a card then discard a card.
Equip {2}

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

Counter target instant or sorcery spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Flying
When Arcanum Owl enters, you may return target instant or sorcery card from your graveyard to your hand.

Lifelink
Arcblade Enforcers gets +1/+1 as long as you control an enchantment.

Wanderlust — When you cast this spell, you may copy it if you control four or more differently named lands.
Exile the top card of your library. Until the end of your next turn, you may play that card. Create a 1/1 Scout creature token that's all colors.

Gain control of target artifact or creature until end of turn. Untap it. It gains haste until end of turn.

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

This spell costs {1} less to cast for each enchantment you control.
Flying, lifelink, trample
Disturb {6}{B}{B}. That spell costs {1} less to cast for each enchantment you control. (You may cast this card from your graveyard transformed for its disturb cost.)

Flying
Concord — When Archangel of Accord enters, if there are four or more card types among permanents you control, destroy all other creatures.

Flying
You may cast enchantment spells from your graveyard.
Whenever an enchantment you control enters, draw a card.

Whenever you cast a noncreature spell, Architect of Calamity deals 2 damage to each opponent.

When Architect of the Derezzed enters, create two 1/1 colorless Servo artifact creature tokens.
Sacrifice an artifact: Target creature can't be blocked this turn.

When Archive Guardian enters, return target card from your graveyard to your hand.
Recite {1}{B}{G} (You may cast this creature from your graveyard for its recite cost. If you do, exile it when it enters or if it would leave the battlefield.)