Mountain

Ride the Rails

Target creature gets +2/+1 until end of turn. (Then exile this card. You may cast the creature later from exile.)

Minecart Daredevil

Minecart Daredevil // Ride the Rails

Not on My Watch

Call a Surprise Witness

Return target creature card with mana value 3 or less from your graveyard to the battlefield. Put a flying counter on it. It's a Spirit in addition to its other types.

Thunder Salvo

Thunder Salvo deals X damage to target creature, where X is 2 plus the number of other spells you've cast this turn.

Plains

Embereth Veteran

{1}, Sacrifice Embereth Veteran: Create a Young Hero Role token attached to another target creature. (If you control another Role on it, put that one into the graveyard. Enchanted creature has "Whenever this creature attacks, if its toughness is 3 or less, put a +1/+1 counter on it.")

Petrify

Enchant artifact or creature
Enchanted permanent can't attack or block, and its activated abilities can't be activated.

Cosmium Blast

Cosmium Blast deals 4 damage to target attacking or blocking creature.

Eriette's Lullaby

Destroy target tapped creature. You gain 2 life.

Helping Hand

Return target creature card with mana value 3 or less from your graveyard to the battlefield tapped.

Shrike Force

Mesa Cavalier

Flying
When Mesa Cavalier enters, you gain 2 life.

Builder's Talent

(Gain the next level as a sorcery to add its ability.)
When Builder's Talent enters, create a 0/4 white Wall creature token with defender.
{W}: Level 2
Whenever one or more noncreature, nonland permanents you control enter, put a +1/+1 counter on target creature you control.
{4}{W}: Level 3
When this Class becomes level 3, return target noncreature, nonland permanent card from your graveyard to the battlefield.

Etali's Favor

Enchant creature you control
When Etali's Favor enters, discover 3. (Exile cards from the top of your library until you exile a nonland card with mana value 3 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)
Enchanted creature gets +1/+1 and has trample.

Heartflame Slash

Heartflame Slash deals 3 damage to any target. (Then exile this card. You may cast the creature later from exile.)

Heartflame Duelist

Instant and sorcery spells you control have lifelink.

Heartflame Duelist // Heartflame Slash

Sheriff of Safe Passage

Sheriff of Safe Passage enters with a +1/+1 counter on it plus an additional +1/+1 counter on it for each other creature you control.
Plot {1}{W} (You may pay {1}{W} and exile this card from your hand. Cast it as a sorcery on a later turn without paying its mana cost. Plot only as a sorcery.)

High Noon

Each player can't cast more than one spell each turn.
{4}{R}, Sacrifice High Noon: It deals 5 damage to any target.

Skewer Slinger

Reach
Whenever Skewer Slinger blocks or becomes blocked by a creature, Skewer Slinger deals 1 damage to that creature.