There is no direct equivalent of *STATIONS and *FSLIST supplied for Acorn file servers, although these SJ Research utilities could be copied into an Acorn file server library and would work perfectly well.
By the days of RISC-OS, Acorn were catching up with this SJ innovation and a list of file servers can be obtained by clicking on the network icon, as shown here on Rob's A5000.
The listing is a little confusing as it lists each file server disc as if it were a separate server. We can see here "CF64M", which is the Station 25 Level 3 server, and the various icons beginning with "FS" are the different discs (or, more accurately, different disc partitions) on the MDFS.
As well as the A5000 being logged onto the network on disc FS2, it is also running Level 4. The monitor screen for Level 4 is shown in the second window, and it has recently been serving stations 101 and 16.