Fifty Feet of Rope

Climb Over — {T}: Target Wall can't block this turn.
Tie Up — {3}, {T}: Target creature doesn't untap during its controller's next untap step.
Rappel Down — {4}, {T}: Venture into the dungeon. Activate only as a sorcery. (Enter the first room or advance to the next room.)

Varis, Silverymoon Ranger

Reach, ward {1}
Whenever you cast a creature or planeswalker spell, 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.)
Whenever you complete a dungeon, create a 2/2 green Wolf creature token.

Secret Door

Defender
{4}{U}: Venture into the dungeon. Activate only as a sorcery. (Enter the first room or advance to the next room.)

Eccentric Apprentice

Flying
When Eccentric Apprentice enters, venture into the dungeon. (Enter the first room or advance to the next room.)
At the beginning of combat on your turn, if you've completed a dungeon, up to one target creature becomes a Bird with base power and toughness 1/1 and flying until end of turn.

Razorclaw Bear

Whenever Razorclaw Bear becomes blocked, it gets +2/+2 until end of turn.

Alpine Grizzly

Shortcut Seeker

Whenever Shortcut Seeker deals combat damage to a player, venture into the dungeon. (Enter the first room or advance to the next room.)

Yuan-Ti Malison

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

You Find a Cursed Idol

Choose one —
• Smash It — Destroy target artifact.
• Lift the Curse — Destroy target enchantment.
• Steal Its Eyes — Create a Treasure token and venture into the dungeon. (Enter the first room or advance to the next room.)

Displacer Beast

When Displacer Beast enters, venture into the dungeon. (Enter the first room or advance to the next room.)
Displacement — {3}{U}: Return Displacer Beast to its owner's hand.

Exuberant Wolfbear

Whenever Exuberant Wolfbear attacks, you may change the base power and toughness of target Human you control to Exuberant Wolfbear's power and toughness until end of turn.

Golden Bear

Professor of Zoomancy

When Professor of Zoomancy enters, create a 1/1 black and green Pest creature token with "When this creature dies, you gain 1 life."

River Bear

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

Wilson, Refined Grizzly

This spell can't be countered.
Vigilance, reach, trample
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Choose a Background (You can have a Background as a second commander.)

Ayula, Queen Among Bears

Whenever another Bear you control enters, choose one —
• Put two +1/+1 counters on target Bear.
• Target Bear you control fights target creature you don't control.

Find the Path

Enchant land
When Find the Path enters, venture into the dungeon. (Enter the first room or advance to the next room.)
Enchanted land has "{T}: Add {G}{G}."

Wandering Troubadour

At the beginning of your end step, if you had a land enter the battlefield under your control this turn, venture into the dungeon. (Enter the first room or advance to the next room.)

Balduvian Bears

Runeclaw Bear

Phantasmal Bear

When Phantasmal Bear becomes the target of a spell or ability, sacrifice it.

Ruxa, Patient Professor

Whenever Ruxa, Patient Professor enters or attacks, return target creature card with no abilities from your graveyard to your hand.
Creatures you control with no abilities get +1/+1.
For each creature you control with no abilities, you may have that creature assign its combat damage as though it weren't blocked.

Striped Bears

Dungeon Delver

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

Forest

Spectral Bears

Whenever Spectral Bears attacks, if defending player controls no black nontoken permanents, it doesn't untap during your next untap step.

Ulvenwald Bear

Morbid — When Ulvenwald Bear enters, if a creature died this turn, put two +1/+1 counters on target creature.

Spirit of the Aldergard

When Spirit of the Aldergard enters, search your library for a snow land card, reveal it, put it into your hand, then shuffle.
Spirit of the Aldergard gets +1/+0 for each other snow permanent you control.

Vivien's Grizzly

{3}{G}: Look at the top card of your library. If it's a creature or planeswalker card, you may reveal it and put it into your hand. If you don't put the card into your hand, put it on the bottom of your library.

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.)

Dragon-Scarred Bear

Formidable — {1}{G}: Regenerate Dragon-Scarred Bear. Activate only if creatures you control have total power 8 or greater.

Enchant creature
Enchanted creature has flying and "Whenever this creature deals combat damage to a player, venture into the dungeon." (Enter the first room or advance to the next room.)

Bar the Gate

Counter target creature or planeswalker spell. Venture into the dungeon. (Enter the first room or advance to the next room.)

Werebear

{T}: Add {G}.
Threshold — Werebear gets +3/+3 as long as seven or more cards are in your graveyard.

Pale Bears

Ellywick Tumblestrum

+1: Venture into the dungeon. (Enter the first room or advance to the next room.)
−2: Look at the top six cards of your library. You may reveal a creature card from among them and put it into your hand. If it's legendary, you gain 3 life. Put the rest on the bottom of your library in a random order.
−7: You get an emblem with "Creatures you control have trample and haste and get +2/+2 for each differently named dungeon you've completed."

Owlbear

Trample
Keen Senses — When Owlbear enters, draw a card.

Bear Cub

Druid's Familiar

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Druid's Familiar is paired with another creature, each of those creatures gets +2/+2.

Island

Owlbear Cub

Mama's Coming — Whenever Owlbear Cub attacks a player who controls eight or more lands, look at the top eight cards of your library. You may put a creature card from among them onto the battlefield tapped and attacking that player. Put the rest on the bottom of your library in a random order.

Grizzly Bears

Surrak and Goreclaw

Trample
Other creatures you control have trample.
Whenever another nontoken creature you control enters, put a +1/+1 counter on it. It gains haste until end of turn.

Copper Host Crusher

Trample
Hexproof (This creature can't be the target of spells or abilities your opponents control.)

Ashcoat Bear

Flash (You may cast this spell any time you could cast an instant.)

Forest Bear

Mother Bear

{3}{G}{G}, Exile Mother Bear from your graveyard: Create two 2/2 green Bear creature tokens. Activate only as a sorcery.

Doric, Owlbear Avenger

Vigilance, trample
When this creature transforms into Doric, Owlbear Avenger, other legendary creatures you control get +2/+2 and gain trample until end of turn.
At the beginning of your upkeep, transform Doric.

Doric, Nature's Warden

Vigilance
When Doric, Nature's Warden enters, search your library for a Forest card, put it onto the battlefield tapped, then shuffle.
Whenever Doric attacks, you may pay {1}{G}. If you do, transform her.

Doric, Nature's Warden // Doric, Owlbear Avenger

Dungeon Descent

Dungeon Descent enters tapped.
{T}: Add {C}.
{4}, {T}, Tap an untapped legendary creature you control: Venture into the dungeon. Activate only as a sorcery. (Enter the first room or advance to the next room.)

Goreclaw, Terror of Qal Sisma

Creature spells you cast with power 4 or greater cost {2} less to cast.
Whenever Goreclaw, Terror of Qal Sisma attacks, each creature you control with power 4 or greater gets +1/+1 and gains trample until end of turn.