Perhaps you have not dipped into the right sources or read material on Sri Aurobindo’s life. I would advice you to read the following biographies.
Sri Aurobindo, his life unique by Rishabhchand
Sri Aurobindo on Himself
Life of Sri Aurobindo by AB Purani
Sri Aurobindo came to me by Dilip Kumar Roy
Twelve years by Sri Aurobindo by Nirodbaran
There are many other accounts of their encounters with Sri Aurobindo documented by Amrita da, Champaklal ji and several others found in various literatures. Amrita da and Sahana di books are among my favorites.
Of course Shyam Kumari di brought out few volumes on encounters of some of the disciples with Sri Aurobindo.
Yes Sri Aurobindo was very reticent to speak about his realisations. Besides they are too many, too vast, too detailed. You will find them in Savitri all his experiences and realisations, as well as in his poems, the prefered mode of most mystics to express their experiences.
To quickly summarise some of his well documented major realisations are the experience of the vacant infinite, the Advaita experience in 1901, that of Nirvana, of inner stillness, and the realisation of the immanent Divine in 1908, the experience of Sarvakhaluvidam Brahman, of Vasudeva everywhere in Alipore Jail, of Parabrahman in 1912, of the complete identification with Sri Krishna in 1926. There are other experiences of the Supramental world and its impact upon his body documented by AB Purani and others around 1918. There are number of others, too many to be recounted.
Speaking of yogic feats, there is the well documented siddhis including Utthapana, Prakamya, bilocation and others. In fact his everyday life is a miracle. For years his daily routine consisted of working almost whole night writing the Arya and the Letters, ‘sleeping’ if sleep that can be called, for couple of hours, eating very little, walking 8 hours a day in his room and remaining in constant meditation. This routine continued even during an experimental total fasting for a month or so. The number of books he wrote in six years of the Arya is itself a sign of a supergenius of the Spirit. There are genuine documented accounts of creating or rather manifesting human bodies for a short while for a particular purpose (I have myself documented one in my videos). His experiences of trikaladrsti are also too well documented. So is his role in turning the tides against Hitler and the Axis powers during the Second World War rather well known with personal accounts of Nazi Camp detainee (Lost footsteps) as well as of others brought together in George Vreikheim book Hitler’s God. Tagore’s account is no less inspiring. His departure itself with the body refusing the law of death and glowing with the supramental light for 111 hours is equally well known and was witnessed by countless persons. There are too many books and videos documenting these to be mentioned. I am not sure what you have read and how come you have missed all these in your research as these are all well known books on Sri Aurobindo.
Having said that Sri Aurobindo himself did not consider any of these as central to yoga. The indispensable experiences on the path are also described at length in his correspondence with the disciples. You will also find plenty of personal accounts of experiences with Sri Aurobindo narrated and recalled by his disciples. The richness and depth of his realisations are truly astounding and his life itself was a miracle if one would say so.
Affectionately,
Alok Da
