On the web new photos appeared on several socket AM4 motherboards, this round it is ASUS and Gigabyte (Aorus). There are four models based on the B350 chipset and one with X370.
You will also spot two micro-ATX boards, the rest obviously has the regular ATX form factor. The photos reveal a thing o two, like USB 3.1 Gen. 2 ports, the Aorus board has a Type-C port. All motherboards have an M.2 slot and check that Aorus AX370, it has 3x PCI-E 3.0 x16.
Have a browse.