Is there a blockland IRC?
Not officially, but there are a few. Notably
#rtb on VoltIRC, and
#rtb2 on QuakeNet.
#rtb was the official Return to Blockland IRC channel, and #rtb2 is the IRC channel for
Port's Transitional RTB.
With players that help you on addons?
Probably not, but you can make your own.
Edit: I would advise registering it with ChanServ, which requires an account from NickServ. That way, you're still the owner of the channel even if you leave it.
