Thundering Mightmare

Soulbond (You may pair this creature with another unpaired creature when either enters the battlefield. They remain paired for as long as you control both of them.)
As long as Thundering Mightmare is paired with another creature, each of those creatures has "Whenever an opponent casts a spell, put a +1/+1 counter on this creature."

Jugan, the Rising Star

Flying
When Jugan, the Rising Star dies, you may distribute five +1/+1 counters among any number of target creatures.

Kura, the Boundless Sky

Flying, deathtouch
When Kura, the Boundless Sky dies, choose one —
• Search your library for up to three land cards, reveal them, put them into your hand, then shuffle.
• Create an X/X green Spirit creature token, where X is the number of lands you control.

Talons of Wildwood

Enchant creature
Enchanted creature gets +1/+1 and has trample. (It can deal excess combat damage to the player or planeswalker it's attacking.)
{2}{G}: Return Talons of Wildwood from your graveyard to your hand.

Spider Umbra

Enchant creature
Enchanted creature gets +1/+1 and has reach. (It can block creatures with flying.)
Totem armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Remnant of the Rising Star

Flying
Whenever another creature enters the battlefield under your control, you may pay {X}. When you do, put X +1/+1 counters on that creature.
As long as you control five or more modified creatures, Remnant of the Rising Star gets +5/+5 and has trample. (Equipment, Auras you control, and counters are modifications.)

Jugan Defends the Temple

(As this Saga enters and after your draw step, add a lore counter.)
I — Create a 1/1 green Human Monk creature token with "{T}: Add {G}."
II — Put a +1/+1 counter on each of up to two target creatures.
III — Exile this Saga, then return it to the battlefield transformed under your control.

Jugan Defends the Temple // Remnant of the Rising Star

Concord with the Kami

At the beginning of your end step, choose one or more —
• Put a +1/+1 counter on target creature with a counter on it.
• Draw a card if you control an enchanted creature.
• Create a 1/1 colorless Spirit creature token if you control an equipped creature.

Kosei, Penitent Warlord

As long as Kosei, Penitent Warlord is enchanted, equipped, and has a counter on it, Kosei has "Whenever Kosei, Penitent Warlord deals combat damage to an opponent, you draw that many cards and Kosei deals that much damage to each other opponent."

Unchecked Growth

Target creature gets +4/+4 until end of turn. If it's a Spirit, it gains trample until end of turn.

Lifespinner

{T}, Sacrifice three Spirits: Search your library for a legendary Spirit permanent card, put it onto the battlefield, then shuffle.

Kodama of the South Tree

Whenever you cast a Spirit or Arcane spell, each other creature you control gets +1/+1 and gains trample until end of turn.

Rending Vines

Destroy target artifact or enchantment if its mana value is less than or equal to the number of cards in your hand.
Draw a card.

Strength of Cedars

Target creature gets +X/+X until end of turn, where X is the number of lands you control.

Briarknit Kami

Whenever you cast a Spirit or Arcane spell, put a +1/+1 counter on target creature.

Kami of Transience

Trample
Whenever you cast an enchantment spell, put a +1/+1 counter on Kami of Transience.
At the beginning of each end step, if an enchantment was put into your graveyard from the battlefield this turn, you may return Kami of Transience from your graveyard to your hand.

Loam Dweller

Whenever you cast a Spirit or Arcane spell, you may put a land card from your hand onto the battlefield tapped.

Kami of the Tended Garden

At the beginning of your upkeep, sacrifice Kami of the Tended Garden unless you pay {G}.
Soulshift 3 (When this creature dies, you may return target Spirit card with mana value 3 or less from your graveyard to your hand.)

Treefolk Umbra

Enchant creature
Enchanted creature gets +0/+2 and assigns combat damage equal to its toughness rather than its power.
Totem armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Kodama's Might

Target creature gets +2/+2 until end of turn.
Splice onto Arcane {G} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Snake Umbra

Enchant creature
Enchanted creature gets +1/+1 and has "Whenever this creature deals damage to an opponent, you may draw a card."
Totem armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Haru-Onna

When Haru-Onna enters the battlefield, draw a card.
Whenever you cast a Spirit or Arcane spell, you may return Haru-Onna to its owner's hand.

Dryad's Favor

Enchant creature
Enchanted creature has forestwalk. (It can't be blocked as long as defending player controls a Forest.)

Krosan Grip

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Destroy target artifact or enchantment.

Feast of Worms

Destroy target land. If that land was legendary, its controller sacrifices another land.

Arashi, the Sky Asunder

{X}{G}, {T}: Arashi, the Sky Asunder deals X damage to target creature with flying.
Channel — {X}{G}{G}, Discard Arashi: Arashi deals X damage to each creature with flying.

Hero's Heirloom

Equipped creature gets +2/+1.
As long as equipped creature is legendary, it has trample and haste.
Equip {2}

Roaring Earth

Landfall — Whenever a land enters the battlefield under your control, put a +1/+1 counter on target creature or Vehicle you control.
Channel — {X}{G}{G}, Discard Roaring Earth: Put X +1/+1 counters on target land you control. It becomes a 0/0 green Spirit creature with haste. It's still a land.

Elder Pine of Jukai

Whenever you cast a Spirit or Arcane spell, reveal the top three cards of your library. Put all land cards revealed this way into your hand and the rest on the bottom of your library in any order.
Soulshift 2 (When this creature dies, you may return target Spirit card with mana value 2 or less from your graveyard to your hand.)

Inner Calm, Outer Strength

Target creature gets +X/+X until end of turn, where X is the number of cards in your hand.