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.

Shield-Wall Sentinel

Defender
When this creature enters, you may search your library for a creature card with defender, reveal it, put it into your hand, then shuffle.

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.

Sylvan Caryatid

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

Rolling Stones

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

Wingmantle Chaplain

Defender
When this creature enters, create a 1/1 white Bird creature token with flying for each creature with defender you control.
Whenever another creature you control with defender enters, create a 1/1 white Bird creature token with flying.

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.

High Alert

Each creature you control assigns combat damage equal to its toughness rather than its power.
Creatures you control can attack as though they didn't have defender.
{2}{W}{U}: Untap target creature.