Yoga Darśana
Sometimes referred to as Classical Yoga, it usually refers to the theory of knowledge, metaphysical inquiry and methodological and contemplative ideas as described in the Pātañjalayogaśāstra or the Yoga Sutras of Patanjali. Not to be confused with Modern Postural Yoga which focuses basically on 1/8 of the system and sees Yoga as a mostly physical exercise.
Haṭha Yoga
The method “of force” as described in the lineage of the Hatha Yoga Pradipika and practice by the Nath sects of India. In an esoteric explanation as expounded in the Yoga Bashya of Vyasa it is explained as the unification, balancing or understanding of the dualistic forces of the body - Ha and Tha. These are paralleled with Prana and Apana (inhale & exhale), up & down, left & right, masculine energies & feminine energies to balance and purify the body to then move to the higher levels of the mind through Raja Yoga.
Raja Yoga
The kingly Yoga to master the levels of the mind and gain control of the vrittis (arising thoughts) and move to the higher states of one pointedness (eka grata ) and liberation (nirodoha)