Prime X399-A Motherboard
This motherboard is for the AMD Threadripper series. I've been running this motherboard and the 1950x on Ubuntu 16.04 for about 8 months and have not had any problems. I chose this one because a lot of the other motherboards with the TR4 socket had a lot of complaints from Linux users, which may have had fixes in place since then.
AMD SocketTR4 EATX motherboard with M.2 Heatsink, DDR4 3600MHz, Dual M.2, U.2, SATA 6Gb/s, Front-panel USB 3.1 Gen 2 connector
Ready for Ryzen™: Latest AMD socketTR4 for Threadripper™ processors.
5-Way Optimisation: One-click, system-wide tuning, delivering optimised overclocks and intelligent cooling for CPU or GPU-intensive tasks.
Industry-leading cooling options: Comprehensive controls for fans and water pumps, via Fan Xpert 4 software or the acclaimed ASUS UEFI.
Next-gen connectivity: Onboard U.2, M.2 and front-panel USB 3.1 Gen 2 connector.
M.2 heatsink: Ultra-efficient heatsink reduces M.2 SSD temperatures by up to 20°C for unthrottled transfer speeds and enhanced reliability.
Aura Sync: Controllable onboard RGB lighting easily syncs with an ever-growing portfolio of Aura Sync-capable hardware.