As of now there is seat left only in North eastern NITs like NIT Mizoram, Nagaland, Agartala, etc. 1 seat is vacant at IIT bhubneswar. These seats are majorly for SC/ST candidates. You can get the full list of vacant seats in the link https://josaa.nic.in/result/root/resultlogin.aspx As of now total of 460 seats are empty.You may need to wait till 30th July to get exact number of seats left, as few people may not report admitting Institute after 7th round (Though this number would be very small) .