Apart from all the usual stuff (DNS, email, NFS, SMB, iSCSI, DHCP, HTTP, Wikis) the biggest thing is as a diskless server. There are many, many boxes here witho

Apart from all the usual stuff (DNS, email, NFS, SMB, iSCSI, DHCP, HTTP, Wikis) the biggest thing is as a diskless server. There are many, many boxes here without disks in them that boot off it from old 386/486s (NE2000s with boot ROMs) through far too many Pis to modern Intel and AMD boxes running various linux and windows version (nice thing about diskless, you can have literally as many different distros as you like on the same PC). Longer term ambition is to get the PDP11's booting off it as well.