What are the best yoga poses for working out my calves?

See below: Pretty much all of the standing yoga asanas with work your calves. The important thing is to focus on proper alignment and build the pose from the ground up by activating all of your muscles in any pose. The provides a whole body work out. Other poses that build the calves would be bridge pose and tip toe bridge pose, all of the warrior series, dancers pose, tree pose and many others.