Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Dryad of the Ilysian Grove

You may play an additional land on each of your turns.
Lands you control are every basic land type in addition to their other types.

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Flooded Strand

{T}, Pay 1 life, Sacrifice Flooded Strand: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Steaming Sauna

(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.)
You have no maximum hand size.
At the beginning of your end step, draw a card.

Roaring Furnace

(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.)
When you unlock this door, this Room deals damage equal to the number of cards in your hand to target creature an opponent controls.

Roaring Furnace // Steaming Sauna

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Mystic Remora

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

Land Tax

At the beginning of your upkeep, if an opponent controls more lands than you, you may search your library for up to three basic land cards, reveal them, put them into your hand, then shuffle.

Command Tower

Entity Tracker

Flash
Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, draw a card.

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

City of Brass

Whenever City of Brass becomes tapped, it deals 1 damage to you.
{T}: Add one mana of any color.

Bloodstained Mire

{T}, Pay 1 life, Sacrifice Bloodstained Mire: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

Inquisitive Glimmer

Enchantment spells you cast cost {1} less to cast.
Unlock costs you pay cost {1} less.

Warped Space

(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.)
Once each turn, you may pay {0} rather than pay the mana cost for a spell you cast from exile.

Charred Foyer

(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.)
At the beginning of your upkeep, exile the top card of your library. You may play that card this turn.

Charred Foyer // Warped Space

Yavimaya, Cradle of Growth

Each land is a Forest in addition to its other land types.

Wooded Foothills

{T}, Pay 1 life, Sacrifice Wooded Foothills: Search your library for a Mountain or Forest card, put it onto the battlefield, then shuffle.

Sol Ring

Marina Vendrell

When Marina Vendrell enters, reveal the top seven cards of your library. Put all enchantment cards from among them into your hand and the rest on the bottom of your library in a random order.
{T}: Lock or unlock a door of target Room you control. Activate only as a sorcery.