There's also the very very cheap Pinebook64 at $100 US. I've played with one: they're built better than they should be for such a cheap machine, but like all Raspberry Pi-wannabe boards, the kernel and graphics support leave much to be desired. Pinebooks were briefly popular from the Amiga emulation crowd (yes, I've been in a room with enough of 'em recently that they can still muster a crowd) who have recently moved on from spending $X,0000 on Qoriq (Power) boards to looking at ARM.

 

Briefly beloved by RMS because they were so open, but painfully slow, and who knew how backdoored in the silicon.

Apart from a 8-core MIPS64 server I saw on Taobao, outside of routers Linux on MIPS lives on in the Onion Omega2, a tiny IOT thing nominally developed out of Markham. It's not much of a Linux computer - 580 MHz MediaTek MT7688, 128 MB RAM, 32 MB flash in the *plus* version - but they're cheap and actually do what they promise, unlike those horrid Intel IOT things from a few years back.