msem-instigator

{T}, Pay 1 life: Add {R} or {W}.
{1}, {T}, Sacrifice Backstage Rooms: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

When Backstage Tinkers enters the battlefield, you may return an artifact card from your graveyard to your hand.

[+1]: Exile up to two target cards from graveyards. You gain 3 life.
[–2]: Exile target artifact, enchantment, or nonbasic land.
[–7]: You get an emblem with “At the beginning of your upkeep, exile target noncreature permanent.”

Flash
Haste
{3}, {T}: Exchange control of two target noncreature spells. Their controllers may choose new targets for the spells.

If you would catalyze, catalyze twice instead. (The next spell you cast this turn costs {1} less to cast.)
You may pay an additional {2} as you cast a spell. If you do, reveal the bottom card of your library. You may put it into your graveyard or on top of your library.

Whenever an artifact or enchantment enters the battlefield under your control, you may detain target nonland permanent. (Until your next turn, that permanent can't attack or block and its activated abilities can't be activated.)

Whenever you detain a permanent, you gain life equal to that permanent's mana value.

Auras and Equipment you control have indestructible.
Whenever Bearidge Marshall attacks, you may create a white Aura enchantment token named Arrest attached to target creature. It has enchant creature and “Enchanted creature can't attack or block, and its activated abilities can't be activated.”

{2}, {T}: Tap target creature.

{T}: Add {G}.
{T}: Add {G}{G}. Activate only if you control an Elemental.

X target creatures can't block this turn.
Fuse (You may cast one or both halves of this card from your hand.)

When Bessie's Brood enters the battlefield, it fights target creature. (If there are no other creatures, it eats itself.)

Trample
Bessie's Crusher has haste as long as you control another Wurm.

[+2]: Create a 3/3 red Wurm creature token.
[–2]: Up to three target creatures each get +2/+2 until end of turn. Bessie deals 2 damage to each of up to three target creatures.
[–9]: You get an emblem with “Creatures you control have base power and toughness 7/7 and have indestructible.”

You may have Better Half enter the battlefield as a copy of any creature on the battlefield, except it's a Reflection in addition to its other creature types and it has distorted. (It can be blocked by tapped creatures but not untapped creatures.)

Exile target card from a graveyard. Create a 1/1 black Worm creature token.
Fuse (You may cast one or both halves of this card from your hand.)

Equipped creature gets +1/+1.
Whenever equipped creature becomes blocked, you may pay {1}{W}. If you do, detain each creature blocking it. (Until your next turn, those creatures can't attack or block and its activated abilities can't be activated.)
Equip {2}

Create a 1/1 blue Bird creature token with flying, then put the bottom card of your library into your hand.

All creatures get -4/-4 until end of turn.

Menace
When Bit Player dies, it deals 1 damage to each opponent.

Trample

Trample, haste
When Blazing Fox enters the battlefield, you may tap an untapped creature you control. If you do, Blazing Fox gets +X/+0 until end of turn, where X is that creature's power.

Target creature gets +2/+2 and gains menace until end of turn.

Trample
Revive {5}{B} ({5}{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.)