Communication
Tools for communication and potentially finding a community.
Discord
A client messenger. Can be used on the web or with a desktop app run in Electron.
Pidgin
Also a client messenger. Supports several chat networks such as IRC, AIM, and Google Talk all in one interface.
Hexchat
A free and open source IRC client that can be run on the three major desktop platforms: Windows, Mac OS, and Linux. You can visit the source code in this GitHub repo.
Personal comment:
Here's the IRC client I personally use.
Rambox
A free and open source software that manages your emails, chat rooms, and online accounts in one window. It is also cross-platform, working on the major platforms especially on Linux where it uses Appimage to distribute it among these systems. Do take note that it has a premium model of the app with extended library of supported apps. To check out the free and open source version of the app, you can visit the GitHub repo.
Slack
A very good chat client between teams especially in a professional environment. Can also be used as a hub for study groups as well.
Personal comment:
Recommended for using it for a group chat. Also supports a lot of integrations as well with the API.
Thunderbird
A free and cross-platform e-mail client made by Mozilla Foundations.
Personal comment:
Free, made by Mozilla, and it has been recently updated.
Personal comment:
Just don't get into the dark side.