I'm using Pidgin, mostly out of nostalgia, but the default configuration basically can't connect to any mainstream messenger these days (Facebook, WhatsApp, Hangouts, Skype or Viber). Plus the UI is so dated, especially regarding emojis.
Before anyone asks, it's in C and I'm nowhere competent (or interested enough in gaining the required competency) to contribute.
With stuff like Pidgin you notice what mindshare really means. A "crappy" Electron based app is nicer to use than the "native" one. In the end, it's all about coders polishing code. No hours put in, no end result coming out.