Dutch tech site Hardware.Info spotted that Asian e-tailers are listing various motherboards from ASRock and Gigabyte. Officially, these boards aren't supposed to be out until about 1.5 months from now, but it looks like they're already circulating.
Ten listings of ASRock motherboards were found, including the H310-HDV, H310-HDV/M.2, B360M-HDV, B360M Pro4, B360 Pro4, B360 Gaming K4, B360M-ITX/ac, H370 Performance, H370M/ITX-ac and H370 Pro4.
Next there are also mentionings of the Gigabyte B360M HD3, B360 Aorus Gaming 3, H370N-WIFI, H370M D3H and H370 Aorus Gaming 3.