Dragonlord's Servant

Dragon spells you cast cost {1} less to cast.

Flameheart Werewolf

Whenever Flameheart Werewolf blocks or becomes blocked by a creature, Flameheart Werewolf deals 2 damage to that creature.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Flameheart Werewolf.

Kessig Forgemaster

Whenever Kessig Forgemaster blocks or becomes blocked by a creature, Kessig Forgemaster deals 1 damage to that creature.
At the beginning of each upkeep, if no spells were cast last turn, transform Kessig Forgemaster.

Kessig Forgemaster // Flameheart Werewolf

Trailblazing Historian

Haste
{T}: Another target creature gains haste until end of turn.

Ardent Elementalist

When Ardent Elementalist enters, return target instant or sorcery card from your graveyard to your hand.

Incendiary Oracle

{1}{R}: Incendiary Oracle gets +1/+0 until end of turn.
If a creature dealt damage by Incendiary Oracle this turn would die, exile it instead.

Arena Trickster

Whenever you cast your first spell during each opponent's turn, put a +1/+1 counter on Arena Trickster.

Plaguecrafter

When Plaguecrafter enters, each player sacrifices a creature or planeswalker of their choice. Each player who can't discards a card.

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

Lightning Visionary

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Young Pyromancer

Whenever you cast an instant or sorcery spell, create a 1/1 red Elemental creature token.

Dragonspeaker Shaman

Dragon spells you cast cost {2} less to cast.

Dragonmaster Outcast

At the beginning of your upkeep, if you control six or more lands, create a 5/5 red Dragon creature token with flying.

Elvish Doomsayer

When Elvish Doomsayer dies, each opponent discards a card.

Genasi Enforcers

Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
{1}{R}: Creatures you control named Genasi Enforcers get +1/+0 until end of turn.

Null Caller

{3}{B}, Exile a creature card from your graveyard: Create a tapped 2/2 black Zombie creature token.

Brallin, Skyshark Rider

Partner with Shabraz, the Skyshark (When this creature enters, target player may put Shabraz into their hand from their library, then shuffle.)
Whenever you discard a card, put a +1/+1 counter on Brallin, Skyshark Rider and it deals 1 damage to each opponent.
{R}: Target Shark gains trample until end of turn.

Spellrune Howler

Whenever you cast an instant or sorcery spell, Spellrune Howler gets +2/+2 until end of turn.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Spellrune Painter

Whenever you cast an instant or sorcery spell, Spellrune Painter gets +1/+1 until end of turn.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Spellrune Painter // Spellrune Howler

Ardent Dustspeaker

Whenever Ardent Dustspeaker attacks, you may put an instant or sorcery card from your graveyard on the bottom of your library. If you do, exile the top two cards of your library. You may play those cards this turn.