msem-instigator

{T}, Pay 1 life: Add {U} or {B}.
{1}, {T}, Sacrifice Unlit Alley: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

At the beginning of your upkeep, each player mills two cards, then reveals the top card of their library and puts it on the bottom of their library.

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)
Tap up to three target creatures. If this spell was kicked, those creatures don't untap during their controller's next untap step.

Target creature you control gains erratic until end of turn. You may have it fight another target creature. (When this creature dies, reveal the top four cards of your library. Put a creature card that costs less than this revealed this way onto the battlefield and the rest on the bottom of your library in any order.)

Unreflected Cultist can't be blocked by Reflections.

Target attacking creature fights another target attacking creature.

Reverberate {2}{R} (When you cast this spell, copy it if you paid its reverberate cost.)
Creatures your opponents control get -2/-0 until end of turn. If Unstable Experiment is reverberated, creatures you control get +1/+0 until end of turn.

Vanishing 2 (This permanent enters with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
{T}: Add {C}.
When Unstable Footing is put into your graveyard from the battlefield, if it had no time counters on it, search your library for a basic land card, put it onto the battlefield, then shuffle.

You may have Unstable Impersonator enter as a copy of any creature on the battlefield chosen at random.

Vanishing 5 (This creature enters with five time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
{1}{R}, Remove a time counter from Unstable Magmaling: Flip a coin. If you win the flip, it deals 3 damage to any target.

When Unstable Orb enters, draw a card.
{3}, {T}, Sacrifice Unstable Orb: It deals 2 damage to target creature.

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
Whenever a creature you control becomes renowned, create a 1/1 red Soldier creature token with haste.

Target attacking creature gets +1/+0 until end of turn. When that creature dies this turn, it deals damage equal to its power to defending player.

For each land you control, you may return a land card from your graveyard to the battlefield tapped.

Look at target opponent's hand, then fateseal 1. (To fateseal 1, look at the top card of an opponent's library, then you may put it on the bottom of that player's library.)

Unwavering Questant can't block.
When an opponent fails a trial, return Unwavering Questant from your graveyard to the battlefield.

Target creature gets -9/-0 until end of turn. Create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

First strike (This creature deals combat damage before creatures without first strike.)

Exile all lands. For each land card exiled this way, Uttermost Obliteration deals 1 damage to that land's controller.

As Vaertris' Master Plan enters, exile the top five cards of any player's library.
You may play cards exiled with Vaertris' Master Plan.
When there are no cards exiled with Vaertris' Master Plan, return it to its owner's hand.

[+1]: Until end of turn, whenever target creature deals combat damage to a player, that player mills two cards.
[–1]: Tap target creature. It can't become untapped for as long as you control Vaertris, Mindmelder.
[–6]: You get an emblem with “Whenever you draw a card, target player mills three cards” and “{2}{U}: Draw a card.”

Search your library for up to three creature cards with mana value 2 or less, put them onto the battlefield, then shuffle.

Creatures you control get +1/+1 until end of turn.
Inscribe {2}{W} ({2}{W}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Motivate 1 (When this creature enters, you may motivate target creature with less power than this by putting a +1/+1 counter on it.)
{2}{W}{W}: Exile Valtrian Cavalier, then return it to the battlefield under your control.

Flying
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)