Irc

Many IRC networks support Tor for connecting, including Ircnow.

You can check Ircnow's Tor servers from the following table:
!!! IRC Servers (by alphabetical hostname order)

IPv4 Server	IPv6 Server	Tor Server	Plain-text port	encrypted port
Associate Servers
`irc.bsdforall.org`	`irc6.bsdforall.org`	`bsdnetoezbtsbrzlnrgxn7iv6qokouuyr4dkd7f2xt6fmmacvi2kjjad.onion`	6667	6697
`irc.ircforever.org`	`irc6.ircforever.org`	`gm7pbm2ukiwbfnhwbqbwa4sie7o4uq24nbzhdlyamutifu7uxwgkymyd.onion`	6667	6697
`irc.ircnow.org`	`irc6.ircnow.org`	`4ufrikyorlatp5ekgz6tlre22v6b5jxqbiid6cp7nuhemklukiohidqd.onion`	6667	6697
`irc.thunderirc.net`	`irc6.thunderirc.net`	`ircnowww2n24aluccfzydqelohej55yrgfkpnp6jc6geijmqht6w77yd.onion`	6667	6697
`irc.novanet.org`	`irc6.novanet.org`	`novanetia3hthx2mlipvunm3akkvreuztojzixxmm527odjax5yvj5ad.onion`	6667	6697

The OFTC Network
For another example, the OFTC network supports Tor directly as well and no registration is needed, for OFTC just use one of the following addresses:

irc.oftc.net:6697
oftcnet6xg6roj6d7id4y4cu6dchysacqj2ldgea73qzdagufflqxrid.onion:6697

SASL may be needed
For some networks you may need to configure SASL for access via Tor. For information on how to do that on irssi check this out for the liberachat network:
/SERVER ADD -ssl -ssl_verify -ssl_capath /etc/ssl/certs -network liberachat -port 6697 irc.libera.chat
/NETWORK ADD -sasl_mechanism plain -sasl_username [username] -sasl_password [password] liberachat
Restart Irssi, connect to the network and look for SASL authentication succeeded message.

Connecting to a shell through Tor
If one is looking for anonymity but doesn't mind revealing the shell being used, the user can connect to a shell (eg. freeirc shell) via Tor and use IRC directly from there:

Install Whonix Gateway and Whonix Workstation to Virtualbox virtualization software:
1. Download Virtualbox for your architecture/distribution and install it
2. Download the Whonix Workstation and Gateway from Whonix.org and follow their guide to install the system to Virtualbox
Use Whonix Workstation to connect through Whonix Gateway (which is Tor-routed) to the shell
Now you connect to the shell via Tor.
1. Boot the Whonix Gateway and Workstation from Virtualbox, (the Workstation uses the Gateway to connect via Tor).
2. Login to the Workstation
3. Type ssh [user]@[server] and press enter
4. Enter the password and you are logged in to your shell server from the Tor network

To connect from the most used IRC clients
irssi
/connect [server] [port]
hexchat
/server [server] [port]