Overgrown Battlement

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

Rampart Architect

Whenever this creature enters or attacks, create a 1/3 white Wall creature token with defender.
Whenever a creature you control with defender dies, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Axebane Guardian

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

Assault Formation

Each creature you control assigns combat damage equal to its toughness rather than its power.
{G}: Target creature with defender can attack this turn as though it didn't have defender.
{2}{G}: Creatures you control get +0/+1 until end of turn.

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.

Rolling Stones

Wall creatures can attack as though they didn't have defender.

Tree of Redemption

Defender
{T}: Exchange your life total with this creature's toughness.

Sylvan Caryatid

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