These days there are very few companies innovating in this space. Oxide is the only one I can think of. (No, HPE and Dell doesn’t count, not in my book at least.)

There used to be lots of them, but they all had a very rough time after the 90s when cheap x86 boxes started to become ubiquitous.

I have no idea if Oxide will succeed or not, but I sure hope so. If it goes well they might become the Sun of the 20s.