If this spell is the first spell you've cast this game, it costs {W} less to cast.
Whenever you cast a spell, you gain 1 life. If that spell is named Leystone of Being, create an X/X white Avatar creature token with lifelink, where X is the difference between your life total and your starting life total.

If this spell is the first spell you've cast this game, it costs {U} less to cast.
Whenever you cast a spell, you may discard a card. If you do, draw a card, then draw two additional cards if that spell is named Leystone of Depths.

If this spell is the first spell you've cast this game, it costs {G} less to cast.
Whenever you cast a spell, put a +1/+1 counter on a land you control. Put four +1/+1 counters on it instead if that spell is named Leystone of Growth. You may have it become a 0/0 Elemental land creature.

If this spell is the first spell you've cast this game, it costs {B} less to cast.
Whenever you cast a spell, target player mills cards equal to its mana value. If that spell is named Leystone of Ruin, they mill twelve cards instead.

If this spell is the first spell you've cast this game, it costs {R} less to cast.
Whenever you cast a spell, Leystone of Storms deals 1 damage to each opponent. If that spell is named Leystone of Storms, instead Leystone of Storms deals 4 damage to any target.

Equipped creature gets +2/+0.
Whenever equipped creature attacks, return target creature card with lesser power from a graveyard to the battlefield under your control tapped and attacking. Exile it at the beginning of the next end step, or if it would leave the battlefield.
Equip {3}

{5}: Lightspeed Cruiser becomes an artifact creature until end of turn.
Crew 2

Attacking creatures you control have first strike.
Whenever you amp it up, draw a card.

{1}, {T}: Target land you control becomes a 4/4 Elemental creature with lifelink, haste, and “When this creature dies, draw a card.” It's still a land. Sacrifice it at the beginning of the next end step.

Whenever Lithe Stalker or another artifact enters under your control, artifact creatures you control gain first strike until end of turn.

Whenever this creature transforms into Lone Switchblade or another permanent you control transforms, each opponent loses 1 life and you gain 1 life.

Flash
Flying, lifelink
Your opponents can't create tokens.

Kraken, Leviathan, Octopus, and Serpent spells you cast cost {X} less to cast, where X is your devotion to blue.

{T}: Add one mana of any color.
As long as you're ancient, lands you you control are every basic land type in addition to their other types.

Flash
When Louna, the Ever-Learning enters the battlefield, for each kind of counter among permanents you control, you may put a counter of that kind on Louna, the Ever-Learning.

Haste
Lucille, Ruthless Warlord has first strike as long as she's attacking.
If another source would deal damage to a permanent other than Lucille or to a player, it deals double that damage to that permanent or player instead.
Escape—{3}{B}{R}, Pay 8 life.

Flying
Lurking Gargoyle enters the battlefield with your choice of counter from among deathtouch, menace or vigilance on it.

Flash
Lyceum Project enters the battlefield with a +1/+1 counter and a flying counter on it.
When Lyceum Project dies, you may put its counters on target creature.

At the beginning of combat on your turn, up to one target creature you control has base power and toughness X/X until end of turn, where X is the number of enchantments you control.
When Lykaretos dies, bless target land.

Indulgence
Whenever you indulge, create a 1/1 blue Gargoyle artifact creature token with flying.

{2}, {T}: Exile target creature you control, then reveal the top card of your library. If the revealed card is a creature card, put it onto the battlefield. Otherwise, return the exiled card to the battlefield under its owner's control.

Deathtouch
Drop — When Malicious Mech enters the battlefield, each player sacrifices a creature. If you didn't cast any creature spells during your last turn, instead each opponent sacrifices a creature.

[+1]: Exile up to one target enchantment or creature. Return it to the battlefield under its owner's control at the beginning of the next upkeep.
[–2]: Exile target creature until target nonland permanent you control leaves the battlefield.
[–4]: You may put a permanent card with mana value 3 or less from your hand or graveyard onto the battlefield.

Flying
When Marbled Messenger enters the battlefield, draw a card.

When Marie Laurent enters the battlefield, you may search your library for a card named Hans Nehmann or Diago Maldovo and reveal that card. If you do, shuffle, then put the card on top of it.
Legendary Allies you control have double strike.