Casal, Pathbreaker Owlbear

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

Casal, Lurkwood Pathfinder

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

Casal, Lurkwood Pathfinder // Casal, Pathbreaker Owlbear

Mother Bear

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

Razorclaw Bear

Whenever this creature becomes blocked, it gets +2/+2 until end of turn.

Spectral Bears

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

Copper Host Crusher

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

Owlbear

Trample
Keen Senses — When this creature enters, draw a card.

Bosco, Just a Bear

When Bosco enters, create a Food token for each legendary creature you control. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
{2}{G}, Sacrifice a Food: Put two +1/+1 counters on Bosco. He gains trample until end of turn.

Spirit of the Aldergard

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

Ulvenwald Bear

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

Rampaging Yao Guai

Vigilance, trample
This creature enters with X +1/+1 counters on it.
When this creature enters, destroy any number of target artifacts and/or enchantments with total mana value X or less.

Pale Bears

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.)

Werebear

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

Evercoat Ursine

Trample
Hideaway 3, hideaway 3 (When this creature enters, look at the top three cards of your library, exile one face down, then put the rest on the bottom in a random order. Then do it again.)
Whenever this creature deals combat damage to a player, if there are cards exiled with it, you may play one of them without paying its mana cost.

Hei Bai, Forest Guardian

When Hei Bai enters, reveal cards from the top of your library until you reveal a Shrine card. You may put that card onto the battlefield. Then shuffle.
{W}{U}{B}{R}{G}, {T}: For each legendary enchantment you control, create a 1/1 colorless Spirit creature token with "This token can't block or be blocked by non-Spirit creatures."

Ruxa, Patient Professor

Whenever Ruxa 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.

Ursine Monstrosity

Trample
At the beginning of combat on your turn, mill a card and choose an opponent at random. This creature attacks that player this combat if able. Until end of turn, this creature gains indestructible and gets +1/+1 for each card type among cards in your graveyard.

Drover Grizzly

Whenever this creature attacks while saddled, creatures you control gain trample until end of turn.
Saddle 1 (Tap any number of other creatures you control with total power 1 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)

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.

Diregraf Scavenger

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When this creature enters, exile up to one target card from a graveyard. If a creature card was exiled this way, each opponent loses 2 life and you gain 2 life.

Grizzly Bears

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 this creature is paired with another creature, each of those creatures gets +2/+2.

Golden Bear

Exuberant Wolfbear

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

Dragon-Scarred Bear

Formidable — {1}{G}: Regenerate this creature. Activate only if creatures you control have total power 8 or greater.

Alpine Grizzly

Professor of Zoomancy

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

River Bear

Ashcoat Bear

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

Bear Cub

Goreclaw, Terror of Qal Sisma

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

Balduvian Bears

Striped Bears

Forest Bear

Kudo, King Among Bears

Other creatures have base power and toughness 2/2 and are Bears in addition to their other types.

Friendly Teddy

When this creature dies, each player draws a card.

Lumra, Bellow of the Woods

Vigilance, reach
Lumra's power and toughness are each equal to the number of lands you control.
When Lumra enters, mill four cards. Then return all land cards from your graveyard to the battlefield tapped.

Owlbear Cub

Mama's Coming — Whenever this creature 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.

Hurska Sweet-Tooth

Whenever Hurska attacks, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
Whenever you gain life, you may pay {G/W}. When you do, target creature gets +X/+X until end of turn, where X is the amount of life you gained.

Runeclaw Bear

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.