Discord is free and is an incredibly strong tool with few limitations. Discord aimed to replace TeamSpeak and Skype but it is such a stable platform with so mu

Discord is free and is an incredibly strong tool with few limitations. Discord aimed to replace TeamSpeak and Skype but it is such a stable platform with so much customization it can be used for almost anything. People even use it as a customer support system or as a command and control center. My university uses Discord, my skydiving club uses Discord, many FOSS communities use Discord. Discord has also open sourced quite a few of their tools. And Discord has always supported the creation of bots via their stable REST api.