When I search online, I can find only a single temple for Ganana Saraswathi in India. The temple is located in Basar, Telangana.
The legend of the temple is mentioned on the temple website
Legend suggest that Maharshi Veda Vyasa, the author of Mahabharata, came to the forests of Dandakaryana to meditate. He began meditating on the banks of the River Godavari and found the place to be very peaceful. The divine mother is believed to have appeared before the sage and ordained him to build temples for the Shakti trio: Maha Saraswathi, Maha Lakshmi and Maha Kali. The sage Veda Vyasa did so by bringing three handfuls of sand and sculpts out the figures. This place was initially named after Vyasa and was called "Vyasapuri". Later on it got took names Vasara and ultimately Basara/Basar.
I feel that there can be more temples that are not popular. Are there any other temples of Gnana Saraswathi in India?