Static: stretches are held steadily, stretching to the farthest point you comfortably can and then holding the stretch. This type is used primarily throughout this website.
Dynamic: involves movement without exceed the range of motion of static stretches.
Active: is a type of static stretching, you stretch one muscle by contracting the opposing muscle.
Pasive: is a type of static stretching in which an external force (partner, therapist, ...) move the limb into the new position.
Ballistic: is a type of dynamic stretching in a bouncing motion, this stretches force the limb into an extended range of motion.
Isometric: is a type of static stretch stretch in which you tense a muscle in order to reduce tension in it.
PNF (Proprioceptive neuromuscular facilitation): is a stretching technique that combine static and isometric streches, begin with a) static stretch, followed b) by an isometric stretch, contracts the tight muscle against the stretch, continue c) relaxing the muscle d) followed by a deeper static stretch in order to gain increased range of motion.