Last month I shared my thoughts on the ASUS E3 PRO GAMING V5 motherboard as a $140 board supporting Intel Xeon E3 v5 CPUs via the Intel C232 chipset. That motherboard was nice, but if your budget is stretched thinner, the ASRock E3V5 WS sells for a little more than $100 and works quite nicely under Linux.
Around the same time as the E3 PRO GAMING V5 I picked up an ASRock E3V5 WS motherboard for use with a spare Xeon E3 v5 CPU and it's worked out very well since. So well, when assembling my most recent Xeon Linux benchmarking system, I opted for the E3V5 WS again. Both of my ASRock E3V5 WS systems have been happily running the past few weeks without any issues to report on.
Of course, for being a board you can easily fetch for $109 USD, it's based on the C232 chipset rather than the C236 chipset of the higher-priced, higher-end motherboards. In going for the lower-end chipset, there are less PCI Express lanes, two less SATA ports, less USB 3.0 ports, and there isn't any support for the integrated graphics on the relevant Xeon models. But if these features aren't relevant to your system's needs, you can be saving at least $50~60 compared to the C236 motherboards.
The ASRock E3V5 WS features six Serial ATA 3.0 ports, "server-grade LAN" (Intel I219LM), DDR4-2133 EUDIMM support, two PCI Express x16 3.0 slots, Realtek ALC892 audio codec, premium 50A power chokes, and an assortment of other ASRock extras. This low-cost Xeon E3 v5 motherboard is an ATX form factor.
While ASRock advertises the E3V5 WS as a server motherboard, only Windows 10 / 8.1 / 7 and Server 2012 / 2008 R2 are listed as supported operating systems... Needless to say with it using the C232 chipset and other common ICs, getting this board working under Linux wasn't any trouble at all. My testing of the two ASRock E3V5 WS systems has been with Clear Linux, Ubuntu 16.04, and Debian Testing. There's been no issues to report in the time I've been using both systems and stressing them daily as part of the LinuxBenchmarking.com performance trackers.
Long story short, I've been using two of the ASRock E3V5 WS motherboards under Linux and they are working out very fine for assembling low-cost Skylake Xeon systems and they've put up quite well with all of the stressing and benchmarking done on them so far via the Phoronix Test Suite. You can see a random assortment of some of the E3V5 WS benchmarks via this OpenBenchmarking.org result file.