One interesting room is irc.sageru.org #jp  -- it has forced anonymous chat. People are weird but not mean. I also like irc.rizon.net #tinychan . Tinychan  is another Anonymous board with an interesting design and lots of activity.
IRC is sort of like discord, but very simple. It's over 32 years old. These days, it's most often used by programmers and the military, but also draws some users from the gaming, anime, and "chan" communities.
 - https://kiwiirc.com/nextclient/irc.sageru.org/#jp
 - https://kiwiirc.com/client/irc.rizon.net/#tinychan
 - https://tinychan.net/