msem-instigator

Creatures can't attack Lord Rickard Dawson unless their controller pays 2 life or discards a card for each creature they control that's attacking him.
[+1]: Create a tapped Treasure token, then you may pay {1}. If you do, each opponent discards a card.
[+1]: You may sacrifice an artifact. When you do, Lord Rickard Dawson deals 3 damage to any target and you gain 3 life.
[–7]: Each opponent gets an emblem with “At the beginning of your end step, if it's not an extra turn, take an extra turn after this one. Target opponent controls you during that turn.”

Flying
When Lord Rokai becomes the target of a spell, sacrifice it.
Whenever you cast an instant or sorcery spell, you may pay {2}{U}. If you do, return Lord Rokai from your graveyard to the battlefield.

Prowess
Whenever you cast a noncreature spell, noncreature spells you cast cost {1} less to cast until end of turn.

(Transcend as a sorcery to gain that type and a +1/+1 counter.)
Lifelink
Demon spells you cast cost {B} less to cast and an additional 2 life to cast.
{3}{B/R}{B/R}: Demon
Discard your hand. Draw a number of cards equal to the greatest power among Demons you control.
{5}{U/B}{U/B}: Noble
Gain control of target creature. You lose life equal to its mana value.

Deathtouch
Artifacts and creatures your opponents control have “At the beginning of your upkeep, you lose 1 life unless you tap this permanent and have an opponent gain control of it.”

Menace
When Lord of Decay enters, put a -1/-1 counter on it and each creature you don't control.

Flying, trample
When Lord of Sacrilege enters, each opponent loses 3 life, discards a card, then sacrifices a nonland permanent. If you control three or more Demons and/or Warlocks, instead each opponent loses 6 life, discards two cards, then sacrifices two nonland permanents.

Other Merfolk you control get +1/+1.
{1}{U}: Target Merfolk gains slipstream until end of turn. (Creatures with slipstream can't be blocked as long as only creatures with slipstream are attacking.)

When Loresprout enters, if you control another creature, draw a card.

(Activate each ability only once as a sorcery. You gain the realm's favor after activating them all.)
{G}: You may play an additional land this turn.
{1}{G}: Search your library for a basic Forest card, reveal it, put it into your hand, then shuffle.
{2}{G}: Search your library for an Elf card, reveal it, put it into your hand, then shuffle.
Favor — Whenever you cast an Elf spell, draw a card.

When Lost Empire's Legacy enters, create two Treasure tokens.
{1}, {T}, Sacrifice an artifact: Return target artifact card from your graveyard to your hand.

Counter target spell, activated ability, or triggered ability. Its controller chooses draw step, main phase, or combat phase. That player skips each instance of the chosen step or phase during their next turn. (Mana abilities can't be targeted.)

Lost Station enters tapped.
{T}: Add {U}.
{U}{U}: Until end of turn, Lost Station becomes a 2/2 Horror creature with “This creature can't be blocked.” Activate only if you're horrific.

Counter target spell. If a noncreature spell is countered this way, conjure a card named Fatigue and put it on top of your library. (It's a colorless sorcery that costs {2} with “Draw a card.”)

Creatures can't attack you or planeswalkers you control unless their controller pays 2 life for each of those creatures.

Play with the top card of your library revealed.
You may play the top card of your library.
At the beginning of your end step, create an X/X green and blue Plant Elemental creature token with reach, where X is the top card of your library's mana value.

Put target artifact or enchantment with mana value less than or equal to the number of basic lands you control on the bottom of its owner's library.

First strike, haste
Whenever Lothaire attacks, create a 0/0 colorless Reflection creature token that's tapped and attacking. Creatures you control get +1/+1 until end of turn.
{2}{R}{W}: Put a +1/+1 counter on each creature you control.

Lotus Lake enters tapped.
{T}: Add {C}.
Landfall — {T}: Add one mana of any color. Activate only if a land you control entered this turn.

Whenever you cast a spell, if the number of petal counters on Lotus Mastery is less than the number of colors of mana spent to cast that spell, put a petal counter on Lotus Mastery and create a Treasure token. Then if there are five or more petal counters on it, sacrifice it and draw five cards.

Deathtouch, lifelink
If a creature would die, exile it instead.
Lotusheart Gorran has all activated and triggered abilities of creature cards exiled with it.

Heretic (Whenever you cast a spell that doesn't share a color with this creature, it gets +1/+1 until end of turn.)
Whenever you cast a white, blue, black, or red spell, add one mana of any color that spell isn't.

Love Letters enters with X stamp counters on it.
Whenever one or more creatures you control deal combat damage to a player, you may remove a stamp counter from Love Letters. If you do, draw a card.

Whenever you make first contact, create a 1/1 white Bird creature token with flying. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)
Whenever three or more creatures you control deal combat damage to a player, create a token that's a copy of another target permanent you control.

{T}: Add {C}.
Motley — {T}: Add one mana of any color. Activate only if there are five or more names among nonland permanents you control.