robinhood_bbc is the most active community
robinhoodbbc_us is spoiler free for American viewers
rh_press is a bi-weekly fandom newsletter

There's fic, tons of icons, links to loads of interviews, there was even art at some point. There's other actor specific communities too, a couple of pairing communities, a fic request comm, uhhh, well, loads. And more treeporn than you can shake a stick at. :DD