msem-instigator

Whenever another creature you control enters, target instant or sorcery card in your graveyard with mana value less than or equal to that creature's power gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

Whenever Ekebram the Scholar becomes untapped, draw a card.
Whenever you draw your third card each turn, you may transform Ekebram.

{1}, {T}: Draw a card, then exile a card from your hand face down.
You may look at cards exiled with Ekebram's Archive.
{4}, {T}, Sacrifice Ekebram's Archive: Return all cards exiled with Ekebram's Archive to their owner's hand.

Indestructible
Whenever a creature you control becomes untapped, draw a card.

When El, Humble Apprentice enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Chosen one ({W}{U}{B}{R}{G}: Transform this permanent.)

{T}: Add {C}.
{2}, {T}: Add {C} for each Desert you control.

Elaborate Firecannon doesn't untap during your untap step.
{4}, {T}: Elaborate Firecannon deals 2 damage to any target.
At the beginning of your upkeep, you may discard a card. If you do, untap Elaborate Firecannon.

Double strike
Whenever Eldan Jackson deals combat damage, return target permanent card with mana value 3 or less from your graveyard to the battlefield.

Whenever Hatsuo attacks, if you control three or more attacking creatures, attacking creatures you control gain first strike until end of turn.
Inspired — Whenever Hatsuo becomes untapped, create a 1/1 white Warrior creature token. It gains haste and attacks this turn if able.

Whenever Chian becomes the target of a spell or ability you control, create a 2/2 blue Drake creature token with flying. This ability triggers only once each turn.

Equipped creature gets +2/+0.
Whenever a creature blocks equipped creature, you may sacrifice Elderbane Rifle. If you do, destroy that creature.
Equip {2}

At the beginning of each combat, you may have Elderin, Crystalline Crusader become a copy of another target creature you control with mana value 3 or less until end of turn, except its name is still Elderin, Crystalline Crusader, it's still 3/3, still legendary, and it's an artifact in addition to its other types.
{W}{U}{B}{R}{G}: Elderin gets +3/+3 until end of turn.

{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.

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

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.

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.