I've got most of my servers sorted out fine so that I only hear notification noises for the ones I care about, however, if discord is hidden behind another program when I hear the noise there's no way to tell if it's from a server I casually care about, or a friend who DM'd me and needs some info right now. If multiple servers are getting lively it can be annoying to keep tabbing out to see if it's important.
Having the ability to set different noises for different servers, channels, DMs or @'s would be useful in knowing if something needs my attention or just wants it.
Custom noises per channel set by the user would be cool but overkill. Just having the choice to set servers/users or general DM's between 3 different preset sounds would be awesome.