As a reminder to myself and as a personal case study in how this experience is now broken for users.

Social

Work

LinkedIn - although mostly I use this as a central depository for all the recruiter messages I end up ignoring.
Slack (for annoying pings that erase your carefully structured, current train-of-thought)
Email (the original high-latency chat app). If you want a good email client recommendation, I recommend Shortwave.
Google Voice - useful for having temporary phone numbers for calls/messages. Recycle occasionally and avoid the buildup of annoying spam!