Kiwi IRC - A hand-crafted IRC client that you can enjoy. Designed to be used easily and freely.
JabbR - A chat application built with ASP.NET and SignalR.
Colloquy - Traditionally, chat clients on the Mac have been anything but glamorous.
AvatarPalace - AvatarPalace is the platform that is used for a chat with others in a 2D virtual world and provides various cartoon characters and fun avatars for a chat.
Terminal on FB Messenger - Take control of your terminal through Facebook Messenger
MyENIGMA - MyENIGMA is an app that allows you to send text messages, videos, audio clips, photos, and files to your friends and family securely.