Been browsing around for a cheap, basic MicroATX motherboard and it looks like Newegg has the ASRock AB350M Pro4 for $49.99 after $10.00 rebate this week. Thought it was a great price for a 4 RAM slot mATX with two m.2 slots, and has the bios already updated to support Ryzen Gen 2.
Reviews have it averaged at 3 eggs, but I personally haven't had any issues. I bought this when it first came out for a Ryzen 1600X build, and between the nvme drive it has been rock solid stable and boots fully to OS in about 8 seconds. With the new bios updates the RAM QVL has been expanded significantly, and I'm now able to run my RAM at its full 2933 speed. I have not attempted to overclock the CPU.
Note: Enabling AMD's advance boot training will prevent you from accessing the bios once ultra-fast boot is enabled. Turn it off and the restart to UEFI app will work again. Took me months to find that solution. Haven't seen any impact on stability.