McKenzie low back extension exercise or yoga cobra's.
Back Extension While Standing
Cat/Camel Exercise
Side-Gliding Lower Back
Side Support Exercise off the Knees
Trunk "Rotisserie"
Back Extension Exercise on Exerball
Spinal Rotation. Inhale, then exhale as the knees and head move in opposite directions. Inhale as you bring the knees and head back to the mid-line and repeat as shown.