I don't even think most of these would hold up in court unless they add "r/" in front of them. Reddit reserves the non-exclusive right to use user content however they want, and I don't think this includes making user-submitted phrases their trademarks. I haven't read the ToS though so another clause might reserve this right too. There might be a claim to words like "subreddit", "r/" and "RPAN" and derivatives because they are based off the "Reddit" trademark.