Underground River

{T}: Add {C}.
{T}: Add {U} or {B}. Underground River deals 1 damage to you.

Nowhere to Run

Flash
When Nowhere to Run enters, target creature an opponent controls gets -3/-3 until end of turn.
Creatures your opponents control can be the targets of spells and abilities as though they didn't have hexproof. Ward abilities of those creatures don't trigger.

Fear of Isolation

As an additional cost to cast this spell, return a permanent you control to its owner's hand.
Flying

Darkslick Shores

Darkslick Shores enters tapped unless you control two or fewer other lands.
{T}: Add {U} or {B}.

Concealed Courtyard

Concealed Courtyard enters tapped unless you control two or fewer other lands.
{T}: Add {W} or {B}.

This Town Ain't Big Enough

This spell costs {3} less to cast if it targets a permanent you control.
Return up to two target nonland permanents to their owners' hands.

Spiteful Hexmage

When Spiteful Hexmage enters, create a Cursed Role token attached to target creature you control. (If you control another Role on it, put that one into the graveyard. Enchanted creature is 1/1.)

Cut Down

Destroy target creature with total power and toughness 5 or less.

Stormchaser's Talent

(Gain the next level as a sorcery to add its ability.)
When Stormchaser's Talent enters, create a 1/1 blue and red Otter creature token with prowess.
{3}{U}: Level 2
When this Class becomes level 2, return target instant or sorcery card from your graveyard to your hand.
{5}{U}: Level 3
Whenever you cast an instant or sorcery spell, create a 1/1 blue and red Otter creature token with prowess.

Locker Room

Whenever one or more creatures you control deal combat damage to a player, draw a card.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Bottomless Pool

When you unlock this door, return up to one target creature to its owner's hand.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Bottomless Pool // Locker Room

Nurturing Pixie

Flying
When Nurturing Pixie enters, return up to one target non-Faerie, nonland permanent you control to its owner's hand. If a permanent was returned this way, put a +1/+1 counter on Nurturing Pixie.

Go for the Throat

Leyline of the Void

If Leyline of the Void is in your opening hand, you may begin the game with it on the battlefield.
If a card would be put into an opponent's graveyard from anywhere, exile it instead.

Temporary Lockdown

When Temporary Lockdown enters, exile each nonland permanent with mana value 2 or less until Temporary Lockdown leaves the battlefield.

Sheltered by Ghosts

Enchant creature you control
When Sheltered by Ghosts enters, exile target nonland permanent an opponent controls until Sheltered by Ghosts leaves the battlefield.
Enchanted creature gets +1/+0 and has lifelink and ward {2}.

Seachrome Coast

Seachrome Coast enters tapped unless you control two or fewer other lands.
{T}: Add {W} or {U}.

Kaito, Bane of Nightmares

Ninjutsu {1}{U}{B} ({1}{U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
During your turn, as long as Kaito has one or more loyalty counters on him, he's a 3/4 Ninja creature and has hexproof.
+1: You get an emblem with "Ninjas you control get +1/+1."
0: Surveil 2. Then draw a card for each opponent who lost life this turn.
−2: Tap target creature. Put two stun counters on it.

Optimistic Scavenger

Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, put a +1/+1 counter on target creature.

Adarkar Wastes

{T}: Add {C}.
{T}: Add {W} or {U}. Adarkar Wastes deals 1 damage to you.

Hopeless Nightmare

When Hopeless Nightmare enters, each opponent discards a card and loses 2 life.
When Hopeless Nightmare is put into a graveyard from the battlefield, scry 2.
{2}{B}: Sacrifice Hopeless Nightmare.