NetIRC2 is an easy-to-use .NET IRC client library. It supports all major features relevant to making a chat client or bot. It has full support for synchronization contexts. You can use it from a Windows Forms or WPF GUI thread and chat events will be automatically dispatched, allowing you to completely ignore multithreading. It uses byte arrays internally, so mixed encodings can be handled. The IrcClient class can even be used as a component in the Forms Designer. Because it speeds up connect times with some IRC servers, an Ident server is included as well.
Ybot is erlang bot software inspired by Github hubot. It supports IRC and XMPP transports and is extensible with plugins. Plugins can be written with Python, Ruby, or shell. It supports IRC chat, XMPP multi user chat, and 37 signals Campfire chat. It can simultaneously run any number of bots on different transports.
err is a plugin-based XMPP chatbot designed to be easily deployable, extensible, and maintainable. It is written in Python, and is based on jabberbot and yapsy with some minor modifications to the first one. It has been tested with HipChat and Openfire, but should be compatible with any XMPP/Jabber servers. It can be set up so that a restricted list of persons have administration rights. Dynamic plugin architecture: the bot admin can install/uninstall/enable/disable plugins dynamically just by chatting with the bot. Supports MUCs (chatrooms). Can proxy and route one to one messages to MUC so it can enable simpler XMPP notifiers to be MUC compatible (such as the Jira XMPP notifier). It is easily extensible. It provides an an automatic persistence store per plugin, and a !help command that dynamically generates the documentation from the Python docstrings of the commands. Create a user for the bot on your private XMPP server or a public server like jabber.org. Optionally, you can create a MUC (also called a conference room or chatroom) in which you can interact with the bot.