I have 50TB of capacity, 30TB used, for Movies and Shows (mostly movies). I get maximum quality 4K Blu-ray rips called Remuxes. For 4K they can be as large as 110GB each movie but never lower than 25GB.
Where I find it is private (torrent) trackers. These places are utopic is what they have available to download and organized to find everything super easy, and the trackers I’m with have a good community and we all talk and hang out in the IRC chat.