msem-instigator

{T}: Add {C}.
{4}, {T}, Sacrifice Elgaud Fortress: Create a token that's a copy of target artifact you control. Activate only as a sorcery.

Choose one —
• Target creature you control deals damage equal to its power to another target creature or planeswalker.
• Target planeswalker you control deals damage equal to the number of loyalty counters on it to target creature or planeswalker.

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.

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

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.

Hexproof, reach

When Elven Guard becomes the target of a spell you control, you may pay {G}. If you do, transform it.

(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.

At the beginning of combat on your turn, look at the top card of your library. You may reveal it. If you do, target creature gets +X/+X until end of turn, where X is the revealed card's mana value.

{4}{G}, Sacrifice Elvish Godtracker: Create a 5/5 green Beast creature token.

When Elvish Skyranger enters, search your library for a card with a basic land type, put it onto the battlefield tapped, then shuffle.

Defiance (Whenever this creature takes damage, if it survives and wasn't defiant, put a +1/+1 counter on it and it becomes defiant.)
At the beginning of your upkeep, if Elvish Songseeker has a +1/+1 counter on it, exile the top card of your library. Until your next turn, you may play that card.

Defiance (Whenever this creature takes damage, if it survives and wasn't defiant, put a +1/+1 counter on it and it becomes defiant.)
{4}{R}: Elvish Verseblade deals 1 damage to each creature. Activate only as a sorcery.

Elfcycling {2}{G} ({2}{G}, Discard this card: Search your library for an Elf card, reveal it, and put it into your hand, then shuffle.)

Whenever Elvish Wayfinder enters or attacks, reveal the top four cards of your library. You may put a land card that doesn't share a name with a land you control into your hand. Put the rest on the bottom of your library in any order.

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.

Haste
At the beginning of your upkeep, sacrifice Ember of Ancient Infernos unless you pay {R}.

Prowess, haste
When Embercore Grazer enters, add {R}{R}{R}. Spend this mana only to cast instant and/or sorcery spells.

First strike
{1}{R}: Transform Embercut Duelist. Activate only if it's attacking.

Defender, reach
{T}, Discard a card: Create a 0/2 red and green Scarecrow creature token with defender and reach.
{R}{G}, {T}: Embergourd Scarecrow deals X damage to target player or planeswalker, where X is the number of creatures with defender you control.

Haste, prowess
{3}{R}, {T}, Sacrifice Emberheart Arcanist: Return target instant or sorcery card from your graveyard to your hand.