Stalwart Shield-Bearers

Defender
Other creatures you control with defender get +0/+2.

Arcane Signet

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

Sporocyst

Ravenous (This creature enters with X +1/+1 counters on it. If X is 5 or more, draw a card when it enters.)
Defender
Spore Chimney — When Sporocyst enters, search your library for up to X basic land cards, put them onto the battlefield tapped, then shuffle.

Arcades, the Strategist

Flying, vigilance
Whenever a creature you control with defender enters, draw a card.
Each creature you control with defender assigns combat damage equal to its toughness rather than its power and can attack as though it didn't have defender.

Sylvan Caryatid

Defender, hexproof
{T}: Add one mana of any color.

Nature's Lore

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

Overgrown Battlement

Defender
{T}: Add {G} for each creature you control with defender.

Wall of Denial

Defender, flying
Shroud (This creature can't be the target of spells or abilities.)

Axebane Guardian

Defender
{T}: Add X mana in any combination of colors, where X is the number of creatures you control with defender.

Bedrock Tortoise

During your turn, creatures you control have hexproof.
Each creature you control with toughness greater than its power assigns combat damage equal to its toughness rather than its power.