I had an HP Microserver N36L since 2011. Despite its low power it served me well as test machine, then converted to a NAS running Debian. When the main disk failed, a >10yo 250GB Seagate Barracuda, it seemed a good time to give a new life to the old but good server. After evaluating some options, the best use for my need was a NAS with options to run Plex and some VMs or containers.
NAS 8Tb low cost, accoppiata HP Microserver / FreeNAS 8.0 –
Installation von FreeNas auf einem HP Micro-Server Gen8
FreeNAS on HP Microserver N54L - Shared Storage for your ESXi
Fresh Install of FreeNAS-11.1 on HPE ProLiant MicroServer Gen10 X3216 – VaiPui
Replacing a Failed Drive on a Gen8 HP Microserver Running FreeNAS – Gav's Tech Blog
Virtual pfSense on FreeNAS - thoughts and performance
Freenas on HP Microserver
Dahilster's Blog: N36L hardware and installing FreeNAS to a USB flash drive
TrueNAS, My new FreeNAS HP ec200a from for $140
Freenas on HP Microserver