This used to be fairly common, back in the old days. Programs like Pidgin unified many messengers into a single app.

For a while, many messengers actually shared underlying protocols (e.g. Google Talk & Facebook were both using XMPP at some point, and you could even cross-message).

Nowadays this is much harder. There's some exceptions (Telegram) with open client protocols, but I wouldn't wanna try and implement something like Discord, it'll be a never-ending tarpit.