msem-instigator

Counter target spell unless its controller pays {4}. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Exile up to one target permanent you control. Return it to the battlefield under its owner's control at the beginning of the next end step.
Recruit. (Create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)

Return any number of lands you control to their owner's hands. For each land returned this way, search your library for a land card, reveal it, then put it into your hand. Then shuffle.

Whenever a creature you control dies, you may pay {G}. If you do, draw a card.

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Whenever a Role becomes attached to Lead Athlete or you cast a spell that targets it, put a +1/+1 counter on Lead Athlete.

Attacking creatures get +2/+0 until end of turn. If you control a legendary creature, those creatures also gain first strike until end of turn.

Whenever Leading Clergy attacks, you may pay {W}. If you do, audition for white. (Create a 1/1 Construct Actor creature token, a Scout Role giving 2/3 and vigilance, or a Cleric Role giving 2/2 and lifelink. Roles replace older ones.)

When Leads Don't Die enters, mill four cards and you gain 4 life.
At the beginning of your upkeep, you may exile X cards from your graveyard and sacrifice Leads Don't Die. When you do, return target creature card with mana value X or less from your graveyard to the battlefield.

When Leafguard Larva enters or a creature scavenges it, return target card from your graveyard to your hand.
Scavenge {3}{G} ({3}{G}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

When Leafmantle Dryad enters, if you control a legendary creature, you may search your library for a basic land card and put it onto the battlefield tapped, then shuffle.

Reach
{1}: Untap Leapweb Lurker.

All creatures have haste and attack each combat if able.
{1}{R}: Led by Fury deals 1 damage to target attacking creature.

Enchant player
At the beginning of enchanted player's upkeep, that player loses 1 life and you gain 1 life.

Bleed {B/R} (You may cast this spell for its bleed cost if an opponent has lost life this turn.)
Left for Carrion deals 4 damage to target creature.

Enchant creature
As Legacy of Siltbottom enters, choose a creature type.
Enchanted creature gets +3/+3 and is the chosen type in addition to its other types.

At the beginning of your end step, draw a card, then discard a card.
Whenever you cast a spell with mana value 5 or greater, if it's an instant or has flash, you may counter target spell.

Vigilance
Creatures you control with a +1/+1 counter on them have mentor. (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Creatures you control with no +1/+1 counters on them have training. (Whenever this creature attacks with another creature with greater power, put a +1/+1 counter on this creature.)

At the beginning of your upkeep, invigorate 1. (Choose a creature with the least power among creatures you control and put a +1/+1 counter on it.)

Put target creature on the bottom of its owner's library.
Each player conjures a card named Fatigue and puts it on top of their library. (It's a colorless sorcery that costs {2} with “Draw a card.”)

You may look at the top card of your library any time.
Once each turn, you may cast a spell from the top of your library.
Whenever you cast a spell from a library, create a 1/1 blue Elemental creature token with vigilance.

Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)
Whenever Leotau Rider encourages a creature, that creature gains trample until end of turn.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever a +1/+1 counter is put onto Lerithan Rebel, it deals 1 damage to any target.

Flying

Enchant creature
Enchanted creature and all other creatures with the same name as that creature can't attack or block.

At the beginning of combat on your turn, create a 1/1 colorless Servo artifact creature token. It gains haste and attacks this turn if able.
Whenever a creature you control dies, you may pay {1}. If you do, put a +1/+1 counter on target creature.