/r/BonerMaterial is a subreddit with no particular focus on any one fetish: it shares material from a number of different subreddits that basically get hosted and reshared here if people think they're good enough to be given the branding of 'boner material'. The homepage of the subreddit pretty much updates with a new batch of content every 24 hours, so it's good for a daily visit to see some pictures of absolutely incredible X-rated material.
I'd say that most of the content is of women, typically naked or close to it, with no male interaction whatsoever. A good quantity is professional, but amateur scenes also sneak into the equation from time to time. The subreddit has no sidebar and as far as I can tell, the only rule is that the content submitted must be capable of inducing a hard on. I think that's pretty much all there is to say, so if it sounds like something you're interested in, head on over to /r/BonerMaterial now to check it out.