Terror of Kruin Pass

Double strike
Werewolves you control have menace. (They can't be blocked except by two or more creatures.)
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Terror of Kruin Pass.

Kruin Outlaw

First strike
At the beginning of each upkeep, if no spells were cast last turn, transform Kruin Outlaw.

Kruin Outlaw // Terror of Kruin Pass

Tovolar's Magehunter

Whenever an opponent casts a spell, Tovolar's Magehunter deals 2 damage to that player.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Tovolar's Magehunter.

Mondronen Shaman

At the beginning of each upkeep, if no spells were cast last turn, transform Mondronen Shaman.

Mondronen Shaman // Tovolar's Magehunter

Plains

Winota, Joiner of Forces

Whenever a non-Human creature you control attacks, look at the top six cards of your library. You may put a Human creature card from among them onto the battlefield tapped and attacking. It gains indestructible until end of turn. Put the rest of the cards on the bottom of your library in a random order.

Wildblood Pack

Trample
Attacking creatures you control get +3/+0.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Wildblood Pack.

Instigator Gang

Attacking creatures you control get +1/+0.
At the beginning of each upkeep, if no spells were cast last turn, transform Instigator Gang.

Instigator Gang // Wildblood Pack

Moonrage Brute

First strike
Ward—Pay 3 life.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Brutal Cathar

When this creature enters or transforms into Brutal Cathar, exile target creature an opponent controls until this creature leaves the battlefield.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Brutal Cathar // Moonrage Brute

Vildin-Pack Alpha

Whenever a Werewolf you control enters, you may transform it.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Vildin-Pack Alpha.

Geier Reach Bandit

Haste
At the beginning of each upkeep, if no spells were cast last turn, transform Geier Reach Bandit.