Here is a selected shortlist from my bookshelf that I think you will find worthwhile – in no particular order.  

(Please let me know if you would like individual recommendations.)

Patanjali’s Yoga Sutra (many translations, some more approachable and some more dense)

The Bhagavad Gita (also many translations)

Hatha Yoga Pradipika

The Radiance Sutras (Lorin Roche)

Ka (Roberto Calasso)

The Mirror of Yoga (Richard Freeman)

Meditation Secrets for Women (Camille Maurine and Lorin Roche)

Tantra Illuminated (Christopher Wallis)

Awakening Shakti (Sally Kempton)

The Key Poses of Yoga (Ray Long)

The Key Muscles of Yoga (Ray Long)

The Art of Vinyasa (Richard Freeman and Mary Taylor)

At the Eleventh Hour (Pandit Rajmani Tigunait)

Path of Fire and Light (Swami Rama)

Yoga of the Subtle Body (Tias Little)

Living with the Himalayan Masters (Swami Rama)

Aghora (Robert Svoboda)

Aghora II: Kundalini (Robert Svoboda)

The Mother (Sri Aurobindo)

Journey to the Mother (Alakananda Ma)

Yoga and Psychotherapy (Swami Rama, Rudolph Ballentine, Swami Ajaya)

Liberation – An Interpretation of Isha Upanishad (Anand Mehrotra)

Becoming Supernatural (Joe Dispenza)

When Love Comes to Light (Richard Freeman and Mary Taylor)

This is That (Anand Mehrotra)

That is This (Anand Mehrotra)