One of my favorite ways of discovering niche content has been browsing /r/all/gilded and taking a look at the variety of highlights throughout the site that never make it to the front page or other kinds of publicity.

I dug in there one time and found a fascinating obituary for a user on a subreddit for people living with addiction -- full of some touchingly personal and weirdly public stories. Following the user's profile from there taught me about the wild world of the "opiate roll call" subreddit (a thinly veiled Craigslist for drugs) which was at the time flourishing. Fascinating stuff.