The GeForce GTX 1660 uses the TU116-300 GPU in combination with 6GB GDDR5 memory clocked 8Gbps. The stock model has a 1530MHz clockspeed and a 1785MHz Boost.
A trio from MSI: GAMING, ARMOR and VENTUS series will all feature a single 8-pin power connector. MSI is also working on VENTUS C and AERO ITX series. Each of these cards will be available in OC and non-OC variants.
A lower-end GeForce GTX 1650 will reportedly follow on April 30th.