Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Command Tower

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

Barrowin of Clan Undurr

When Barrowin enters, venture into the dungeon. (Enter the first room or advance to the next room.)
Whenever Barrowin attacks, return up to one creature card with mana value 3 or less from your graveyard to the battlefield if you've completed a dungeon.

Rhet-Tomb Mystic

Flying
Each creature card in your hand has cycling {1}{U}. ({1}{U}, Discard that card: Draw a card.)

Fact or Fiction

Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Selfless Spirit

Flying
Sacrifice this creature: Creatures you control gain indestructible until end of turn.

Island

Bartolomé del Presidio

Sacrifice another creature or artifact: Put a +1/+1 counter on Bartolomé del Presidio.

Dalkovan Encampment

This land enters tapped unless you control a Swamp or a Mountain.
{T}: Add {W}.
{2}{W}, {T}: Whenever you attack this turn, create two 1/1 red Warrior creature tokens that are tapped and attacking. Sacrifice them at the beginning of the next end step.

Contaminated Landscape

{T}: Add {C}.
{T}, Sacrifice this land: Search your library for a basic Plains, Island, or Swamp card, put it onto the battlefield tapped, then shuffle.
Cycling {W}{U}{B} ({W}{U}{B}, Discard this card: Draw a card.)

Faithful Mending

You gain 2 life, draw two cards, then discard two cards.
Flashback {1}{W}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Isolated Chapel

This land enters tapped unless you control a Plains or a Swamp.
{T}: Add {W} or {B}.

Archetype of Imagination

Creatures you control have flying.
Creatures your opponents control lose flying and can't have or gain flying.

Dungeon Delver

Commander creatures you own have "Room abilities of dungeons you own trigger an additional time."

Planar Ally

Flying
Whenever this creature attacks, venture into the dungeon. (Enter the first room or advance to the next room.)

Triumphant Adventurer

Deathtouch
During your turn, this creature has first strike.
Whenever this creature attacks, venture into the dungeon. (Enter the first room or advance to the next room.)

Cathar Commando

Flash
{1}, Sacrifice this creature: Destroy target artifact or enchantment.

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Sefris of the Hidden Ways

Whenever one or more creature cards are put into your graveyard from anywhere, venture into the dungeon. This ability triggers only once each turn. (To venture into the dungeon, enter the first room or advance to the next room.)
Create Undead — Whenever you complete a dungeon, return target creature card from your graveyard to the battlefield.

Thriving Moor

This land enters tapped. As it enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Port Town

As this land enters, you may reveal a Plains or Island card from your hand. If you don't, this land enters tapped.
{T}: Add {W} or {U}.

Meteor Golem

When this creature enters, destroy target nonland permanent an opponent controls.

Agna Qel'a

This land enters tapped unless you control a basic land.
{T}: Add {U}.
{2}{U}, {T}: Draw a card, then discard a card.

Curate

Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
Draw a card.

Priest of Fell Rites

{T}, Pay 3 life, Sacrifice this creature: Return target creature card from your graveyard to the battlefield. Activate only as a sorcery.
Unearth {3}{W}{B} ({3}{W}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Doomed Necromancer

{B}, {T}, Sacrifice this creature: Return target creature card from your graveyard to the battlefield.

Doom Whisperer

Flying, trample
Pay 2 life: Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Temple of Deceit

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {U} or {B}.

Sunken Hollow

({T}: Add {U} or {B}.)
This land enters tapped unless you control two or more basic lands.

Hama Pashar, Ruin Seeker

Room abilities of dungeons you own trigger an additional time.

Sun Titan

Vigilance
Whenever this creature enters or attacks, you may return target permanent card with mana value 3 or less from your graveyard to the battlefield.

Arcane Sanctum

This land enters tapped.
{T}: Add {W}, {U}, or {B}.

Collector's Vault

{2}, {T}: Draw a card, then discard a card. Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Vohar, Vodalian Desecrator

{T}: Draw a card, then discard a card. If you discarded an instant or sorcery card this way, each opponent loses 1 life and you gain 1 life.
{2}, Sacrifice Vohar: You may cast target instant or sorcery card from your graveyard this turn. If that spell would be put into your graveyard, exile it instead. Activate only as a sorcery.

Obsessive Stitcher

{T}: Draw a card, then discard a card.
{2}{U}{B}, {T}, Sacrifice this creature: Return target creature card from your graveyard to the battlefield.

Mulldrifter

Flying
When this creature enters, draw two cards.
Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Merfolk Looter

Dungeon Map

{T}: Add {C}.
{3}, {T}: Venture into the dungeon. Activate only as a sorcery. (Enter the first room or advance to the next room.)

Angel of the Ruins

Flying
When this creature enters, exile up to two target artifacts and/or enchantments.
Plainscycling {2} ({2}, Discard this card: Search your library for a Plains card, reveal it, put it into your hand, then shuffle.)

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Orzhov Signet

Blazing Archon

Ravenous Chupacabra

When this creature enters, destroy target creature an opponent controls.

Myr Battlesphere

When this creature enters, create four 1/1 colorless Myr artifact creature tokens.
Whenever this creature attacks, you may tap X untapped Myr you control. If you do, this creature gets +X/+0 until end of turn and deals X damage to the player or planeswalker it's attacking.

Cataclysmic Gearhulk

Vigilance
When this creature enters, each player chooses an artifact, a creature, an enchantment, and a planeswalker from among the nonland permanents they control, then sacrifices the rest.

Geth, Lord of the Vault

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
{X}{B}: Put target artifact or creature card with mana value X from an opponent's graveyard onto the battlefield under your control tapped. Then that player mills X cards.

Ardyn, the Usurper

Demons you control have menace, lifelink, and haste.
Starscourge — At the beginning of combat on your turn, exile up to one target creature card from a graveyard. If you exiled a card this way, create a token that's a copy of that card, except it's a 5/5 black Demon.

Vile Entomber

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When this creature enters, search your library for a card, put that card into your graveyard, then shuffle.

Oriq Loremage

{T}: Search your library for a card, put it into your graveyard, then shuffle. If it's an instant or sorcery card, put a +1/+1 counter on this creature.

Victimize

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

Fates' Reversal

Return up to one target creature card from your graveyard to your hand. Venture into the dungeon. (Enter the first room or advance to the next room.)

Yuan-Ti Malison

This creature can't be blocked as long as it's attacking alone.
Whenever this creature deals combat damage to a player, venture into the dungeon. (Enter the first room or advance to the next room.)

Troll of Khazad-dûm

This creature can't be blocked except by three or more creatures.
Swampcycling {1} ({1}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)

Dread Return

Return target creature card from your graveyard to the battlefield.
Flashback—Sacrifice three creatures. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Go for the Throat

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice this artifact: Draw a card.

Utter End

You Find the Villains' Lair

Choose one —
• Foil Their Scheme — Counter target spell.
• Learn Their Secrets — Draw two cards, then discard two cards.

Goring Ceratops

Double strike
Whenever this creature attacks, other creatures you control gain double strike until end of turn.

Thorough Investigation

Whenever you attack, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Whenever you sacrifice a Clue, venture into the dungeon. (Enter the first room or advance to the next room.)

White Plume Adventurer

When this creature enters, you take the initiative.
At the beginning of each opponent's upkeep, untap a creature you control. If you've completed a dungeon, untap all creatures you control instead.

Thriving Isle

This land enters tapped. As it enters, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. This artifact deals 1 damage to you.

Darkwater Catacombs

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Midnight Pathlighter

Creatures you control can't be blocked except by legendary creatures.
Whenever one or more creatures you control deal combat damage to a player, venture into the dungeon. (Enter the first room or advance to the next room.)

Accursed Marauder

When this creature enters, each player sacrifices a nontoken creature of their choice.

Caves of Koilos

{T}: Add {C}.
{T}: Add {W} or {B}. This land deals 1 damage to you.

Exotic Orchard

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

Disenchant

Swamp

Plains

Nadaar, Selfless Paladin

Vigilance
Whenever Nadaar enters or attacks, venture into the dungeon. (Enter the first room or advance to the next room.)
Other creatures you control get +1/+1 as long as you've completed a dungeon.

Shriekmaw

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
When this creature enters, destroy target nonartifact, nonblack creature.
Evoke {1}{B} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Temple of Silence

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {W} or {B}.

Ashen Rider

Flying
When this creature enters or dies, exile target permanent.

Radiant Solar

Flying, lifelink
Whenever this creature or another nontoken creature you control enters, venture into the dungeon. (Enter the first room or advance to the next room.)
{W}, Discard this card: Venture into the dungeon and you gain 3 life.

Cloudblazer

Flying
When this creature enters, you gain 2 life and draw two cards.

Choked Estuary

As this land enters, you may reveal an Island or Swamp card from your hand. If you don't, this land enters tapped.
{T}: Add {U} or {B}.

Buried Alive

Search your library for up to three creature cards, put them into your graveyard, then shuffle.

Azorius Signet

Thriving Heath

This land enters tapped. As it enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

Dimir Signet

Twilight Diviner

When this creature enters, surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
Whenever one or more other creatures you control enter, if they entered or were cast from a graveyard, create a token that's a copy of one of them. This ability triggers only once each turn.

Glacial Fortress

This land enters tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Immovable Rod

You may choose not to untap this artifact during your untap step.
Whenever this artifact becomes untapped, venture into the dungeon.
{3}{W}, {T}: For as long as this artifact remains tapped, another target permanent loses all abilities and can't attack or block.

Negate

Rilsa Rael, Kingpin

Deathtouch
When Rilsa Rael enters, you take the initiative.
Whenever you attack, target attacking creature gains deathtouch until end of turn. If you've completed a dungeon, that creature also gets +5/+0 and gains first strike and menace until end of turn.