Secret Tunnel

This land can't be blocked.
{T}: Add {C}.
{4}, {T}: Two target creatures you control that share a creature type can't be blocked this turn.

Grizzly Bears

Ashcoat Bear

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

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.

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.)

Unnatural Growth

At the beginning of each combat, double the power and toughness of each creature you control until end of turn.

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.

Ayula's Influence

Discard a land card: Create a 2/2 green Bear creature token.

Bear Cub

Werebear

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

Mother Bear

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

Runeclaw Bear

Balduvian Bears

The Earth King

When The Earth King enters, create a 4/4 green Bear creature token.
Whenever one or more creatures you control with power 4 or greater attack, search your library for up to that many basic land cards, put them onto the battlefield tapped, then shuffle.

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.

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.