The Celestus

If it's neither day nor night, it becomes day as The Celestus enters.
{T}: Add one mana of any color.
{3}, {T}: If it's night, it becomes day. Otherwise, it becomes night. Activate only as a sorcery.
Whenever day becomes night or night becomes day, you gain 1 life. You may draw a card. If you do, discard a card.

Storm-Charged Slasher

At the beginning of combat on your turn, target creature you control gets +2/+0 and gains trample and haste until end of turn.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Reckless Stormseeker

At the beginning of combat on your turn, target creature you control gets +1/+0 and gains haste until end of turn.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Reckless Stormseeker // Storm-Charged Slasher

Unnatural Moonrise

It becomes night. Until end of turn, target creature gets +1/+0 and gains trample and "Whenever this creature deals combat damage to a player, draw a card."
Flashback {2}{R}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Moonrager's Slash

This spell costs {2} less to cast if it's night.
Moonrager's Slash deals 3 damage to any target.

Frenzied Trapbreaker

{1}, Sacrifice Frenzied Trapbreaker: Destroy target artifact or enchantment.
Whenever Frenzied Trapbreaker attacks, destroy target artifact or enchantment defending player controls.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Outland Liberator

{1}, Sacrifice Outland Liberator: Destroy target artifact or enchantment.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Outland Liberator // Frenzied Trapbreaker

Arlinn, the Moon's Fury

Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)
+2: Add {R}{G}.
0: Until end of turn, Arlinn, the Moon's Fury becomes a 5/5 Werewolf creature with trample, indestructible, and haste.

Arlinn, the Pack's Hope

Daybound (If a player casts no spells during their own turn, it becomes night next turn.)
+1: Until your next turn, you may cast creature spells as though they had flash, and each creature you control enters with an additional +1/+1 counter on it.
−3: Create two 2/2 green Wolf creature tokens.

Arlinn, the Pack's Hope // Arlinn, the Moon's Fury

Rockfall Vale

Rockfall Vale enters tapped unless you control two or more other lands.
{T}: Add {R} or {G}.

Tovolar's Packleader

Whenever Tovolar's Packleader enters or attacks, create two 2/2 green Wolf creature tokens.
{2}{G}{G}: Another target Wolf or Werewolf you control fights target creature you don't control.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Tovolar's Huntmaster

When Tovolar's Huntmaster enters, create two 2/2 green Wolf creature tokens.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Tovolar's Huntmaster // Tovolar's Packleader

Howl of the Hunt

Flash
Enchant creature
When Howl of the Hunt enters, if enchanted creature is a Wolf or Werewolf, untap that creature.
Enchanted creature gets +2/+2 and has vigilance.

Untamed Pup

Trample
Other Wolves and Werewolves you control have trample.
{3}{G}: Put a +1/+1 counter on target creature.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Hound Tamer

Trample
{3}{G}: Put a +1/+1 counter on target creature.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Hound Tamer // Untamed Pup

Wing Shredder

Reach
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Bird Admirer

Reach
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Bird Admirer // Wing Shredder

Cathartic Pyre

Choose one —
• Cathartic Pyre deals 3 damage to target creature or planeswalker.
• Discard up to two cards, then draw that many cards.

Mountain

Lord of the Ulvenwald

Other Wolves and Werewolves you control get +1/+1.
Whenever Lord of the Ulvenwald attacks, add {R} or {G}. Until end of turn, you don't lose this mana as steps and phases end.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Kessig Naturalist

Whenever Kessig Naturalist attacks, add {R} or {G}. Until end of turn, you don't lose this mana as steps and phases end.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Kessig Naturalist // Lord of the Ulvenwald

Tovolar, the Midnight Scourge

Whenever a Wolf or Werewolf you control deals combat damage to a player, draw a card.
{X}{R}{G}: Target Wolf or Werewolf you control gets +X/+0 and gains trample until end of turn.
Nightbound

Tovolar, Dire Overlord

Whenever a Wolf or Werewolf you control deals combat damage to a player, draw a card.
At the beginning of your upkeep, if you control three or more Wolves and/or Werewolves, it becomes night. Then transform any number of Human Werewolves you control.
Daybound

Tovolar, Dire Overlord // Tovolar, the Midnight Scourge

Unnatural Growth

At the beginning of each combat, double the power and toughness of each creature you control until end of turn.