Hatha Yoga	Includes the practice of postures (asanas) and breath control (pranayama) to energize the subtle channels (nadis), removing obstacles to samadhi or non-duality. Read more in Hatha Yoga.
Laya Yoga	Is also called Kundalini Yoga, because the raising of Kundalini energy to unite her with the supreme consciousness is the main objective, which is reached through deep meditation (dhyana).
Mantra Yoga	Through the repetition of a mantra or seed sound, a higher state of deep concentration (dharana) can be reached at which the divine form inherent in the mantra becomes manifest. Read more in Mantra Yoga.
Raja Yoga	Is also called the royal path of Yoga, where centralized thought combined with spiritual reflection allows the withdrawal from sensory perceptions, leading to deep meditation (dhyana) and samadhi. It is the yoga of Patanjali.

Other Yoga Traditions :

Krya Yoga	This yoga has a strong connection to Karma yoga and Kundalini yoga, involving pranayama, ritual and deep meditation. Read more in Kriya Yoga.
Naad Yoga	Yoga that deals with the sounds of the inner world.
Yantra Yoga	Yantras are seen as the body or form of the deity, whereas mantras are the mind, consciousness, spirit or name. Yantras and mantras can bring one in attunement with the same regulating forces that have created nature in all its forms, including the structure of our psyche and our capacity to think. The discipline is used to withdraw consciousness from the outer world and direct it to the inner world. It consists both of the act of drawing and painting the yantra as of centering on the yantra, reconstructing it first within the mind. More information and yantra samples can be found on the Yantra Meditation page.
Swara yoga	This is the science of nasal breath, providing a practical method to use the right and left hemispheres of the brain at will. It deals with the relationship between the nasal breath and the subtle nerves of the body or nadis, on the one hand, and the cycles of the Moon and the elements, on the other. Swara Yoga offers methods for determining right/left nostril dominance and for synchronizing the dominant nostril with specific activities of everyday life. See also Swara Yoga.

The above overview was extracted and synthesized by Wil Geraets from various sources, among which the following are the most important :

• the "Chakras" book, which offers detailed information on all main yoga techniques and on chakra meditation, which involves all aspects of Ashtanga Yoga.
  
• The "Tools for Tantra" book, which offers highly detailed information on Mantra and Yantra Yoga.
  
• The "Breath, Mind and Consciousness" book, which is the main book on Swara Yoga.