msem-instigator

Aristocrat's Gallery enters tapped.
When Aristocrat's Gallery enters, look at the top card of your library. You may put it into your graveyard.
{T}: Add {G} or {U}.

{T}, Pay 1 life: Add {G} or {U}.
{2}, {T}, Sacrifice Alchemist's Laboratory and another permanent: Draw a card. Activate only during your turn.

{T}, Pay 1 life, Sacrifice Abbey of Masquerades: Create a tapped Plains token, Island token, Swamp token, Mountain token, or Forest token.
Lifecycle {3} ({3}, Discard this card: Create two tapped 1/1 colorless Elemental creature tokens.)

When Unmarked Vials enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
{1}, {T}: Add one mana of any color.

Strider Engine enters tapped and with a -1/-1 counter on it unless you spent at least three colors of mana to cast it.

Prowess
Pay 2 life: Change a target of target spell or ability to Straw Intellectual.

As Stained Reliquary enters, choose a card type.
{T}: Target player exiles a card from their graveyard of the chosen type.
{2}, Exile Stained Reliquary: Exile all graveyards. Create a tapped 1/1 white Spirit creature token with flying.

Equipped creature gets +3/+1 and has reach.
Equip {4}

{T}: Add one mana of any color.
{4}, {T}, Sacrifice Prototype Engine: Put four -1/-1 counters on target creature.

Deploy 4 (As this enters, you may tap any number of other creatures you control with total power 4 or more.)
When Mechanical Tactician enters deployed, tap up to two target creatures an opponent controls. Those creatures don't untap during their controller's next untap step.

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

Equipped creature gets +4/+3.
Equip—{2}, Put a -1/-1 counter on a creature you control.

When Celestial Scythe enters, attach it to target Angel, Demon, Faerie, or Spirit you control.
Equipped creature gets +2/+1.
Equip {2}

Whenever you untap a nonland permanent, put a winding counter on Barton's Pocketwatch.
{T}: Look at the top card of your library. You may put it into your graveyard. Then if Barton's Pocketwatch has twelve or more winding counters on it, exile it and take an extra turn after this one.

When Barking Irons enters, if it's not a token, create a token that's a copy of it.
Equipped creature gets +2/+0.
Equip {2}

Whenever you cast an instant or sorcery spell, put a loyalty counter on Xenocrata and tap up to one target permanent.
[0]: Each opponent can't untap more than three permanents during their next untap step.
[–3]: Xenocrata deals 6 damage divided as you choose among any number of target creatures and/or planeswalkers.
[–9]: Cast any number of instant and/or sorcery cards you own in exile and from your graveyard without paying their mana costs.

Flash
When Witch of the Veil enters, if it was cast, you may sacrifice a creature. If you do, return that card to the battlefield under its owner's control.

Angels, Demons, Faeries, and Spirits you control get +1/+1.
{2}{W}{B}, Pay 1 life, Discard a card: Create a tapped 1/1 white Spirit creature token with flying.

Disgraced 1 (This enters with a -1/-1 counter. Whenever it deals combat damage to a player, remove all -1/-1 counters from it.)
Whenever you put one or more -1/-1 counters on Scion of Fiends or another creature, Scion of Fiends deals that much damage to each opponent.

Whenever Mysteries of Life enters or you create a token, choose one that hasn't been chosen this turn —
• You gain 2 life.
• Draw a card, then discard a card.
• You may tap or untap target permanent.

[+2]: Target player exiles a card from their hand at random. Until the end of that player's next turn, they may play that card.
[0]: Gain control of target creature or planeswalker until end of turn. Tap it.
[–9]: Take an extra turn after this one. During that turn, you control all opponents.

Kanvar can't attack or block.
Whenever a creature you control with power 4 or greater dies, draw a card.
{R}{G}, {T}: Copy target triggered ability you control. You may choose new targets for the copy. (A triggered ability uses the words “when,” “whenever,” or “at.”)

This spell costs {1} less to cast for each permanent sacrificed this turn.
Fallen Sluagh can't be blocked by creatures with power 2 or less.

[+1]: Create a 1/1 red Human creature token with haste.
[–2]: Untap all creatures you control. Until end of turn, they gain “{T}: This creature deals 1 damage to each opponent.”
[–6]: You get an emblem with “Whenever a creature becomes tapped, this emblem deals 2 damage to any target and you gain 2 life.”

When Benthic Alchemist enters, draw a card, then discard a card, then mill a card.
Whenever you cast an instant or sorcery spell, create a 1/1 colorless Elemental creature token. It gains haste until end of turn.