Axebane Guardian

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

Perimeter Captain

Defender
Whenever a creature you control with defender blocks, you may gain 2 life.

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.

Stalwart Shield-Bearers

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

Overgrown Battlement

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