Long before OnlyFans and ManyVids came along, there was Clips4Sale. This was the original adult video clips platform that started way back in 2003. It has survived through to the present day while other pale imitations have come and gone.
Clips4Sale (or C4S as it's commonly known) tends to be the place where you may find video clips of the more unusual fetishes. There are so many categories to browse through it's hard to count them all, and there are certain to be many there that you hadn't ever thought of. There are mainstream categories, sure, but it's the fetish ones that have the most content available in them. For example there are 2540 movies in the "teens" category but right below that there are more than twice that many under the heading "teeth fetish". Now, tell me that you were aware there even was a "teeth" fetish?
The design of the site looks a little dated and old school but that kind of fits with the nature of the content. The videos are produced by various "studios" and you can browse by studio as well as category, or just by the latest added clips. Pricing seems to be loosely related to the length of the video, so short ones can be had from $6.99 or so and longer full length ones go up to $31.99 or more. Which, you may realize, is more than you will pay to join an entire porn paysite for a month. However, it may be that this is the only place you can find that exact video of that particular fetish and I guess if people weren't paying those prices they wouldn't be able to charge them. And with over 17 million visitors per month they probably don't have a shortage of customers. In fact I know a good number of adult producers do very well out of just uploading movies to C4S alone.
Anyway, if you're into some really weird sexual activity and you want to find some porn that contains it, Clips4Sale is the most likely place to start looking.