The two I linked at the start of this thread, Rising Stars and Temari's, are both pretty chill -- so if you're interested in what they have to offer, I can guarantee they'll be sanitized.
Same with another group, PvPrincesses. The folks that come out to the queue syncs are just there to play the game in coordinated groups and would be more than happy to teach someone some good Frontlines cadence.
Revival's had some moderation issues in the past, due to it's size and the mods being an all-volunteer force, but it's much better now.
PvPrimal is also fine. Mostly a hub for organizing games to play, playing them, and going home.
There's one for OCE and EU too, but I don't hang around there often enough to know if they're clean. Aussies can be brutal lol