The best ones are internal Bloomberg terminal chats inside a firm. =) Okay, admittedly tongue and cheek and not the most helpful answer what what you are hoping to find. But I would suggest what you're wanting to find does not legitimately exist for the retail market. If someone's business is to make money trading, they are not going to share their liquidity with anyone else, and they don't need retail momentum from chat followers to drive price.
Any room that relies on subscription revenue to make money isn't going to be a consistently helpful in the long run in terms of finding trade locations.
So the best rooms therefore I would suggest are private admission only. If you must find a chat room, then find the private ones.
In case I misread your question and you mean what chat software to use...then I apologize...
There are many chatrooms and idea of being inside is that you can't handle everything. People who are there give you alerts what's moving, what's worth watching, their thoughts and so on. Some of people give you entry points, tell you direction where stock will probably move. That's why I ask if anyone knows any chatrooms. I am currently in 4 and still looking for better ones.
I think the problem with that kind of chatrooms is: you don't know if the tips you receive are meant to trip you up or not. Some people may be posting what looks like advice on entry points but they may be taking a position against you.
I would concur with what MN said. I'd also recommend that an impartial squawk service is better than any chat room.
One of the best things I've done recently that has improved my trading immensely was to ditch the chat rooms, Twitter and every other kind of distraction I might have. If you are 100% completely new to trading then you should be reading books, reading threads here, watching Youtube videos on the FIO channel, etc. Chat rooms will only confuse you when you are brand new.
Once you have a better understanding of the market and are developing and testing plans and methods, I think a chat room could be helpful if you find a like minded person to interact with. The danger at this point is following someone elses ideas to the detriment of your own development.
Once you have a method that you trust in back testing and/or paper trading you should be focusing effort on live trading that plan; this is where a chat room will just be a distraction.
I do belong to a chat room but I rarely log in anymore; the last time I did was last week when the DB news hit...I went on to see if anyone knew what was going on, got my answer and logged off. I can tell you that I wasted a lot of energy in that particular chat room. Everyone was well intended and no one was selling useless shit so I actually got very lucky that all I really lost was time and focus. Most lose a lot more.
One guy in the room, who trades ES like me, would always post trades, talk about them, give advice, etc. He seemed very knowledgeable and he won some and lost some, so also honest. The biggest thing is that he came across as someone who was a real source of trading information, someone who knew what he was doing. I came to learn through one of his posts that he's not even trading real money, he's still on sim. My reaction was more wtf is this guy doing posting trades, posting his daily P&L and talking about trading psychology like he knows something and he's not even trading real money!
This guy wasn't a moderator or affiliated with the website, just a guy who I think was honestly trying to help. That's probably the best case scenario. I suspect that most people in chat rooms are like this with the exception that they are the ones running the room and taking your money.
The frustrating thing for me about chatrooms is that everyone wants to use them for trade entries. Equities based chatrooms are particularly awful. Sharing old tips so that you can buy the high's of impulse moves. I don't want to follow someone else's trades. I just want to talk to other traders about trading, and maybe what they did last weekend.