I would recommend opening an All the Mods 3 server. I have no idea how big the player base for Stonebound is anymore but All the Mods 3 has added many newly update mods such as Thaumcraft and EnderIO. I haven't played Revelations recently so I have no idea what is in that pack.
we had one, it died due to inactivity https://forums.stonebound.net/topic/1419/all-the-mods-3-server-opening
FTB Continuum just released
yup, gonna see if its any good this weekend and then decide if its worth running, keep an eye on #general on discord for more updates on that