Generally AMD’s Polaris lineup of GPUs are a good fit for the the HoneyComb. First their power consumption is more inline with a HoneyComb build, secondly they have very good upstream support. Most the HoneyComb users that are using their machine for a desktop are using Polaris based cards, so there is also very good community support. One community member did do a bringup on a Navi based card, but the lowest powered option runs at twice the power consumption of the LX2160a at idle.
Additionally there are a number of community members that use Nvidia GTX 7xx based cards. They have recently received clock support so run decently, but are not as well supported as AMD’s options. Anything newer than the 7xx series have only basic support with OSS drivers and therefore run, but very slowly.