Harald Unites the Elves

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Mill three cards. You may put an Elf or Tyvar card from your graveyard onto the battlefield.
II — Put a +1/+1 counter on each Elf you control.
III — Whenever an Elf you control attacks this turn, target creature an opponent controls gets -1/-1 until end of turn.

Swamp

Llanowar Elves

Circle of Dreams Druid

{T}: Add {G} for each creature you control.

Lys Alana Huntmaster

Whenever you cast an Elf spell, you may create a 1/1 green Elf Warrior creature token.

Elvish Pioneer

When Elvish Pioneer enters, you may put a basic land card from your hand onto the battlefield tapped.

Elves of Deep Shadow

{T}: Add {B}. Elves of Deep Shadow deals 1 damage to you.

Tyvar Kell

Elves you control have "{T}: Add {B}."
+1: Put a +1/+1 counter on up to one target Elf. Untap it. It gains deathtouch until end of turn.
0: Create a 1/1 green Elf Warrior creature token.
−6: You get an emblem with "Whenever you cast an Elf spell, it gains haste until end of turn and you draw two cards."

Elvish Harbinger

When Elvish Harbinger enters, you may search your library for an Elf card, reveal it, then shuffle and put that card on top.
{T}: Add one mana of any color.

Llanowar Mentor

{G}, {T}, Discard a card: Create a 1/1 green Elf Druid creature token named Llanowar Elves. It has "{T}: Add {G}."

Fabled Passage

{T}, Sacrifice Fabled Passage: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

Forest

Immaculate Magistrate

{T}: Put a +1/+1 counter on target creature for each Elf you control.

Wren's Run Vanquisher

As an additional cost to cast this spell, reveal an Elf card from your hand or pay {3}.
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)