Deep breathing exercise, Sukha Purvaka (easy comfortable) Pranayama during walking, Pranayama during meditation, Rhythmical breathing, Suryabheda, Ujjayi, Sitkari, Sitali, Bhastrika, Bhramari, Murchha, Plavini, Kevala Kumbhaka, and others are among the many variations of Pranayama exercises available to fit various constitutions, temperaments, and purposes. Only the last eight of the above exercises are mentioned in Hatha Yogic texts.
NADI SUDDHI
However, you must first cleanse the Nadis before beginning to practice Pranayama. Only then would you be able to get the most out of Pranayama. Samanu or Nirmanu—that is, with or without the use of Bija—is used to cleanse the Nadi (Nadi-Suddhi).
The Yogi in Padmasana or Siddhasana, according to the first form, offers his prayers to the Guru and meditates on him. He does Japa by Ida of the Bija 16 times, Kumbhaka with Japa of the Bija 64 times, and then exhalation through the solar Nadi and Japa of Bija 32 times while meditating on ‘Yang' (y:). Manipura's fire is summoned and joined with Prithvi's.
Then inhale through the solar Nadi 16 times with the Vahni Bija ‘Rang' (r), Kumbhaka 64 times with Japa of the Bija, and exhale through the lunar Nadi 32 times with Japa of the Bija. He then gazes at the tip of his nose, meditating on the lunar brilliance, and inhales 16 times by Ida with Japa of the Bija ‘Thang' (Y).
Kumbhaka is performed 64 times with the Bija ‘Vang' (v:). He imagines himself as being flooded with nectar and that the Nadis have been cleansed. He exhales 32 times by Pingala with Japa of the Bija ‘Lang' (l:) and finds himself improved as a result.
You may also want to read more about Pranayama and Holistic Healing here.