Sol Ring

Shield Sphere

Defender
Whenever Shield Sphere blocks, put a -0/-1 counter on it.

Warmonger's Chariot

Equipped creature gets +2/+2.
As long as equipped creature has defender, it can attack as though it didn't have defender.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Plains

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.

Forest

Memnite

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Ornithopter

Grizzled Leotau

Accorder's Shield

Equipped creature gets +0/+3 and has vigilance. (Attacking doesn't cause it to tap.)
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)