When I started out running HA, I had it on a Raspberry Pi like a lot of people, but got annoyed by the slow CPU and the lack of memory, which made it frustrating to do stuff like work on fixing bugs in some of the modules I use. So I looked around for fanless small-form-factor computers with more horsepower. I ended up getting a Fitlet 2. It’s an x86 PC so you can install any standard Linux distro you want, no need for Pi-specific ones; I went with Ubuntu 18.04.
I’ve now had it for just over six months and it has been rock-solid reliable and remains pleasantly fast. Definitely not as cheap as a Pi, but I consider it money well spent. Figured it was worth mentioning here since there are occasionally people asking about NUCs and other Pi alternatives.