msem-instigator

Menace
{3}{B}, Discard a card: Unhallowed Singers gets +3/+0 until end of turn. Whenever it deals combat damage to a player this turn, they discard a card.

{T}: Add one mana of any color.
{T}, Sacrifice Unicorn of the Vale: Add three mana of any one color.

Whenever you cast an enchantment spell, reveal the top card of your library. If it's an enchantment card, you may put it onto the battlefield.

If you would draw a card, you may return an instant or sorcery card from your graveyard to your hand instead.
{U}: Draw three cards.

When Unite Against Evil enters, return target creature card with mana value 3 or less from your graveyard to the battlefield.
Menagerie — Whenever you attack, if there are five or more creature types among creatures you control, put a +1/+1 counter on target attacking creature and untap it.

Look at the top six cards of your library. Put up to two creature cards with mana value 3 or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order. Then you gain 1 life for each Angel, Demon, Faerie, and/or Spirit you control.

Each artifact you control has all the activated abilities of other artifacts you control.

Exile the top five cards of your library. Until end of turn, you may play any number of cards exiled this way with mana value less than or equal to the number of colors among permanents you controlled as you cast United Fervor.

Enchant creature
As long as it's your turn, enchanted creature has indestructible.
Whenever enchanted creature attacks, it deals damage equal to its toughness to any target.

Lifelink
Augmented — Whenever you cast a spell, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on United Guardian. It loses this ability and gains “Whenever United Guardian attacks, create two 1/1 blue Elemental creature tokens with flying that are tapped and attacking.”

Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)
United Patrol can block an additional creature each combat.

Until end of turn, you can't lose the game, your opponents can't win the game, and your life total can't change.

When United in Battle enters, look at the top six cards of your library. You may reveal a Dwarf or Elf card from among them and put it into your hand. Put the rest on the bottom in a random order.
Whenever a Dwarf or Elf you control enters, put a +1/+1 counter on it.

When Unity Spheres enters, create two 1/1 colorless Construct artifact creature tokens.
Tap two untapped creatures you control: Add two mana of any one color.

Creatures you control have base power 4 and gain trample until end of turn.

Gain control of target creature with power less than or equal to the number of different creature types among creatures you control.

Return target creature card from your graveyard to the battlefield, then search target opponent's library for a creature card and put that card onto the battlefield under your control. Then that player shuffles.

Flying
Whenever you cast a spell from your graveyard, return Unliving Swarm from your graveyard to your hand.

Gain control of target nonland permanent if you control a permanent with a greater mana value. Otherwise, destroy that permanent.

{6}{W}: Tap all creatures target player controls.

Whenever a creature dies, you may put a progress counter on Unorthodox Methods.
[progress 2-6] Whenever you cast a noncreature spell, Unorthodox Methods deals 2 damage to any target and you gain 2 life.
[progress 7+] Whenever you cast a noncreature spell, Unorthodox Methods deals 4 damage to any target and you gain 4 life.
Whenever you cast a noncreature spell, CARDNAME deals 4 damage to any target and you gain 4 life.

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.

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.)

Draw two cards. Then target opponent may give themselves two poison counters. If they don't, draw two cards.
{1}, Discard Unravel Prophecy: Add one mana of any color. Scry 1.