msem-instigator

(Transform this if it's not attached to a creature. Pay {3}{G} as a sorcery to unattach it.)
Enchant creature you control
Elven Mount's rider gets +3/+3 and has trample.

Scry 2. (Then exile this card. You may cast the creature later from exile.)

Ember Salvo deals 1 damage to target creature and 1 damage to its controller.

When Emberling dies, it deals 1 damage to any target.

Whenever you cast a noncreature spell, upgrade Embodied Soul. (Give it one of the listed counters it doesn't already have.)
• Flying
• First strike
• Vigilance
• Lifelink
{W}: Until end of turn, if Embodied Soul isn't a creature, it becomes a 0/0 Spirit Avatar enchantment creature with “This creature gets +1/+1 for each different kind of counter on it.”

Whenever you discard a card this turn, add {B}. Then you may cast that card. (You still pay its costs.)

{T}: Add {W} or {U}. You lose 1 life unless you have less life than an opponent.

Legendary creatures you control get +1/+1.

Target creature you control gets +X/+X until end of turn, where X is the number of +1/+1 counters among creatures you control.

Enchant creature
Enchanted creature gets +1/+0 and has menace and haste.
You may cast Empty the Magazine from your graveyard by paying {3}{R} rather than paying its mana cost.

Create a token that's a copy of target nonland permanent you control with mana value X.
Flashback—{U}{U}, Exile cards from your graveyard with exactly X card types among them. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

{T}: Add {C}.
Concord — {T}: Create a Treasure token. Activate only if there are four or more card types among permanents you control.

{U}, Put a travel counter on Endless Discoveries: Draw a card. This ability costs {1} more to activate for each travel counter on Endless Discoveries.
{3}{U}{U}, Sacrifice Endless Discoveries: Return target instant or sorcery card with mana value less than or equal to the number of travel counters on Endless Discoveries from your graveyard to your hand.

Archive 3 (As this enters, shuffle the top three cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever you draw a card from the archived library, put the top card of your main library on the bottom of the archived library.
{B}: Exchange a card from the archived library with a card from your hand.

When Endless Trove enters, if it's not a token, each opponent may create a token that's a copy of it.
{T}: Add one mana of any color.

{T}: Add {C}.
{3}, {T}, Sacrifice Enduring Vestige: Search your library for a land card with a basic land type, put it onto the battlefield tapped, then shuffle.

Destroy target creature. You lose 4 life.

{U}: If Engrossed Reader doesn't have flying, put a flying counter on it.
{1}{U}: If Engrossed Reader has flying, draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on Engrossed Reader.
{1}{U}{U}: If Engrossed Reader has a +1/+1 counter on it, it becomes a copy of another target creature until end of turn.

Choose a card name, then look at the top card of your library. If it has the chosen name, you may exile it and you may play it from exile until end of turn.
Whenever a creature you control becomes tapped, you may return Enigma of Seventy Scrolls from your graveyard to your hand.

Recruit. (Create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)

Prowess

Enchant opponent
At the beginning of enchanted player's upkeep, they choose one that hasn't been chosen yet —
• They discard three cards.
• They sacrifice three nonland permanents.
• You transform Enrapturing Grudge.
If Enrapturing Grudge would be put into a graveyard from anywhere, exile it instead.

Enshrouded Village enters tapped.
{T}: Add {G}.
{1}{G}{G}: Until end of turn, Enshrouded Village becomes a 4/4 Human creature with trample. Activate only if you're horrific.

Enchant creature
Enchanted creature has reach. (It can block creatures with flying)
{G}, Sacrifice Ensnaring Vines: Tap target creature with flying.

Whenever you make first contact, Entelan Idealist gets +2/+2 until end of turn. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)