As another alternative to the likes of the SiFive HiFive Premier P550 RISC-V developer board, the Andes Voyager is in the process of seeing patches reviewed for mainline Linux kernel support.
The Andes Voyager is a micro-ATX RISC-V board built around the QiLai SoC and features a 16GB DDR4 SIMM socket, one PCI Express 4.0 x16 slot for a graphics card, two additional PCI Express 4/0 x4 slots, an NVMe slot, and other basics.
The QiLai SoC provides a quad-core RISC-V AX45MP cluster clocking up to 2.2GHz and one NX27V vector processor clocking up to 1.5GHz.
Andes Tech supports openSUSE Linux on this Voyager development platform while mainline kernel support for it can open the door for other RISC-V Linux distributions appearing on the board.
This patch series is currently being reviewed that provides the basic Device Tree support for both the QiLai SoC and the Voyager development board. Follow-on patches are expected to add additional features/drivers for going beyond the basic functionality of this board. More details on the Voyager for those interested via AndesTech.com.