There are a number of Hindu Yogis who have extensive writings online, all free

They include Swami Vivekananda (his complete works are online, free)

Sri Aurobindo

Sri Ananda Moi Ma

Paramahansa Yogananda

Sri Ramana Maharishi

Mahatma Gandhi's writings are also online.

Just Google the names and websites will come up...

Mahatma Gandhi considered both Paramahansa Yogananda and Swami Vivekananda to be true saints.

And Paramahansa Yogananda considered Sri Ananda Moi Ma and Sri Ramana Maharishi to be true saints.