msem-instigator

When Elderthrone Castellan enters, you may search your library for a Plains card, reveal it, put it into your hand, then shuffle.

{T}: Add one mana of any color.
{T}, Sacrifice Elderthrone Shard: Draw a card.

Whenever one or more creatures you control deal combat damage to a player or planeswalker, create a Clue token.
{G}{U}, Sacrifice a Clue: Put a +1/+1 counter on target creature. Proliferate.

{0}: Until end of turn, Eldritch Egg becomes a copy of target permanent card in a graveyard with mana value 6 or less except it's an artifact. Activate only once each turn. (It has no other card types.)

[progress 2+]
[progress 5+]
Whenever a creature enters, each opponent loses 1 life.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, you may have Elegant Fireslinger deal 1 damage to target creature.

Elemental Envelopment enters with X +1/+1 counters on it.
When Elemental Envelopment enters, if you controlled a green legendary creature or planeswalker as you cast it, search your library for any number of Elemental creature cards with total mana value X or less, where X is Elemental Envelopment's power, put them onto the battlefield, then shuffle.

{T}: Add {C} and one mana of any color.

When Elemental Loremaster enters, return an instant or sorcery card at random from your graveyard to your hand.

Flash
Creatures you control that have entered this turn get +1/+1 and have haste and first strike.

Reach
Whenever Elemental of Vengeance is dealt damage, it deals damage equal to its power to any target.

Equipped creature gets +1/+1 and has prowess.
Equip {2}

[+1]: Create a tapped colorless Bullet artifact token with “{T}, Sacrifice this artifact: It deals 1 damage to any target.”
[–1]: Exile target creature or planeswalker that was dealt damage this turn.
[–7]: You get an emblem with “At the beginning of each end step, you may draw X cards, where X is the amount of life your opponents lost this turn.”

At the beginning of combat on your turn, creatures you control gain your choice of trample, menace, haste, or +1/+0 until end of turn.

{1}{R}, {T}, Sacrifice an artifact: Elise, Maktali Prodigy deals 2 damage to any target.
{1}{U}, {T}, Sacrifice an artifact: Return target nonland permanent to its owner's hand.
{3}{U}{R}, {T}, Sacrifice three artifacts: Discard your hand, then draw seven cards.

{2}, {T}: You gain 5 life. Shuffle Elixir of Immortality and your graveyard into their owner's library.

Flash
Prowess
When Ella enters, create two 1/1 blue Wizard creature tokens with prowess.
Whenever you cast a noncreature spell, you may sacrifice a creature. If you do, copy that spell. You may choose new targets for the copy.

At the beginning of your upkeep, you may search your library for a permanent card with mana value 1 or less, put it onto the battlefield, then shuffle.

During each of your turns, you may cast a card with a cycling ability from your graveyard by discarding a card in addition to paying its other costs. If that spell would be put into your graveyard, exile it instead.
Cycling {2} ({2}, Discard this card: Draw a card.)

Elrayin, the Manaroot enters tapped.
Whenever you tap another land for mana, put a creation counter on Elrayin.
{T}, Remove ten creation counters from Elrayin and sacrifice it: Untap all lands target player controls.

{1}, {T}: Exile target creature you control until Elsewhere Mirror leaves the battlefield. (It returns to the battlefield under its owner's control.)
{3}: Choose a permanent card exiled with Elsewhere Mirror. Target creature becomes a copy of that card until end of turn.

[+1]: Create a 1/1 white Warrior creature token.
[–1]: Another target permanent you control gains indestructible until your next turn.
[–8]: You get an emblem with “Creatures you control get +2/+2.” and “Prevent all damage that would be dealt to attacking creatures you control.”

Whenever you cast an instant or sorcery spell, exile cards from the top of your library until you exile an instant or sorcery card. You may cast that card until you exile another card with this ability.

Hexproof
When Elusive Devout enters, choose one —
• Put a +1/+1 counter on Elusive Devout.
• Create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”