Yoga, the system of spiritual salvation of ancient Indian yogis developed over many centuries or even thousands of years. This led to some evolutions and changes in yoga. These evolutions resulted in evolution of yoga in many different forms Mantra yoga, Bhakti Yoga, Jnana Yoga, Karma Yoga, Kundalini Yoga, Kriya Yoga, Raja Yoga etc…
The main four among them are Raja Yoga, Karma Yoga, Bhakti Yoga and Jnana Yoga. All the yoga types are interrelated in different forms. Their ultimate goal and practice have marked similarities. Total exclusion of a type of yoga from another type really is not possible.
Raja Yoga is the set of yoga sutra as set by Patanjali the yogi seer. Yoga Sutra by Patanjali has the eight step path to salvation and it is called Astanga Yoga.
Karma Yoga puts emphasis on attaining salvation by virtue of selfless actions and duty. Though it sound very simple, this state is very difficult to achieve. The yogi doesn’t remain knowledgeable, but only the result of his duty remains. The yogi can’t expect even a word of appraisal in return of his/her karma.
Bhakti Yoga is a means of attaining salvation by virtue of relentless faith on the almighty. The person completely surrenders before his/her God. The sole focus of meditation is on his or her God and the person slowly and completely surrenders before the supreme consciousness. The person will be able to identify himself with his supreme master and this is the state of moksha.
Jnana Yoga is the method of Gods. Jnana means knowledge and Jnana Yoga is the method of attaining salvation through the knowledge of ultimate wisdom on the purpose of man. There is no point in believing, but only realization. The person possesses the knowledge of the secrets of universe and the purpose of human life. The person experience knowledge and self awareness. The person knows the union of mind and soul.
Mantra yoga is attainment of moksha by chanting mantras or enchantments. Kundalini Yoga is the methods of awakening centers of psychic knowledge located in knowledge chakras along the Kundalini (spinal cord). Kriya Yoga is a set of activities designed to awaken the consciousness. Swara Yoga is method to attain union with soul by means of controlling breath.
There are many different types of yoga evolved over many years, which have different forms. Describing all of them are not possible and sometime not appropriate.