No one else cares to share some? There must be lots more which we don’t know about.
omg omg omg keep these coming all!
I used to like www.pornwall.com a lot during the past. It’s not too extreme though. Also, if you like amateurs, you can find some real cunts on www.eroxia.com .
Check these ones out
https://www.extremetube.com/
https://www.daftporn.com/
http://www.brutaltube.xxx/
Free extreme content must be hard to find, right guys? I for one don’t have patience to download movies from forums. There must be online delights that aren’t hidden in the dark web too.
Define “extreme” 
There’s a nice mashup site to watch several videos at the same time… (instead of mashing up 4 vlc players LOL). No own content though… It’s pornhub based… Anyway…
I’d say extreme would be something that you cannot see on regular porn sites. Categories that are so kinky, they exceed most people’s imagination. For example, I wouldn’t say this is extreme, but vacuum cleaner masturbation videos aren’t popular or a niche… they are weirder, they don’t focus on how good the people look… they just present a raw type of sexual play and release. Scat is extreme if you ask me… zoo porn the same…
Try some of these
If you are into forced sex movie you can visit https://bestrapeporn.com/ the site is new, but the video are great with regular update !
Please define extreme. For instance I decided not to publish shemale material on Lust Core as looked too manly and totally puts me off. So that can be extreme from a certain point of view. However I already have shemale latex material on Lust Core that can be also considered extreme. Oh yes, the site is free and that won’t change, ever. So tell me what do you want to see and I am happy to consider.