Besides the 'Shri Sai Satcharita' and 'Guru Charitra', what other, less famous, Guru biographies does the text mention?

The preface does mention other Guru biographies that are not as prominent. Chapter 0 references a detailed and scholarly biography written by Shri Samarth Sadguru Tembhe Swami, also known as Vasudevanand Saraswati Maharaj. It is noted, however, that this work has not achieved the same fame as the 'Guru Charitra' and is in a different category because the Guru wrote it himself. Additionally, the text mentions hearing about a Guru biography by Shri Samarth Sadguru Dattatreya Maharaj of Balekundri, but it was believed to be unprinted and unpublished at the time the preface was written.