These five motherboards will be more at home powering a server than a high end gaming machine as they fully support Intel's Xeon E3-1200 v5 and other LGA 1151 processors, all but two offer ECC memory compatibility using Intel's C236 and C232 chipset. That doesn't mean you shouldn't consider them for your next build as they should offer rock solid stability and hey, they're camouflaged!
Up first are the X170-EXTREME ECC and X150-PRO ECC, with the first PCIe 3.0 16x slot connected directly to the CPU socket, no detours for that data. The boards support PCIe Gen.3 x4 NVMe M.2 natively and you can pick up a U.2 converter if that is what you need for your drives and Intel's USB 3.1 controller will give you performance on both the original flavour and Type-C USB ports. The X170 Extreme comes with a Killer E2400 Gigabit NIC, along with all of the benefits provided by that chip.
Up next are the X150M-PRO ECC, X150M-PLUS WS and X150-PLUS WS motherboards which are listed on Gigabyte's site. The X150M-Pro is mATX but Gigabyte still managed two PCIe 16x slots, with one limited to 4x speeds and a pair of PCI slots along with an M.2, 6 SATA 6Gbps and a SEx connector. The X150M Plus is very similar but sports a single PCIe 16x and a 4x no legacy connectors nor a SEx port. Finally the full ATX GA-X150-PLUS WS which adds a pair of PCIe x1 slots in addition to two PCIe 16x slots, with one limited to 4x speeds and a pair of PCI slots.