Olimex OLinuXino LIME2 - I really like this single board computers, and use one for a lot of my selfhosting. They have a SATA connector, backup battery connector and Gbit ethernet. If that wasn't good enough it's even open hardware! It is also one of the few boards which runs with completely free software, including the bootloader. I have a special relation to this board in particular, as I started my selfhosting journey with one of them. Today, they it is not really competitive in terms of performance for the price, the SOC is relatively weak, but it's still more than enough for many selfhosting tasks.
ROCKPro64 - I've been using this board for some time now as a NAS and media server. It does things like automated media downloading and protects against bitrot using snapraid. It's a lot more powerful than the lime2, and has a PCIe 4x slot you can use to connect a bunch of hard drives to it. As I understand, you can run this board almost entirely with free software, apart from some binary blobs needed for hardware initialization during boot.
PinePhone Pro - As the years have gone by, I have found myself less and less satisfied with Android, partly to me feeling that it's been getting more bloated as time goes on. Switching to a linux phone is something I would like to do in the future. The first PinePhone has matured into something which is usable by enthusiasts. The PinePhone Pro is basically a big hardware upgrade over the original PinePhone. I'm carefully watching this to see how it evolves.