My DH has hoarding tendencies, as does my FIL.
My DH has a much stronger emotional attachment and memory attachment to his belongings than I do. He believes if he throws things away, he will forget his past, but also he will loose a part of himself.
He hoards a lot of media. For instance, one of the things he hoards is books. Many of the books he has never even read, but he won't part with them. He treats each book like it is the last copy of that book in the world, so it would be a travesty to part with it. I have actually seen him upset when he has been asked to go through his books and get rid of a few (we were moving house so there was a reason for this). He will tell you when he bought the book, and where, and say it was a happy experience, so he can't get rid of it. And even though he has never read it he intends to (and yet he has still never read it!!). Same with vinyl, cds, cassettes, videos, dvds. We have so many and they're all his. He has memories and intentions attached to each one.
But he also hoards rubbish, like flyers, free magazines, packaging etc.
He also hates minimalist houses. He has criticised friend's houses saying "I don't trust them, where is all their stuff?" which makes no sense to me. He obviously equates belongings with personality, and feels unsure about people who have few belongings.
I dont know if it's relevant, but we have 2 autistic children, so there's a chance DH could have some traits or be autistic, but he's never been assessed so I couldn't say either way.
My DD who is definitely autistic shows similar hoarding tendencies to DH, she certainly can't get rid of anything with a face (like a previous poster) so she owns loads of soft toys, and won't get rid of any unless she's giving it to someone she knows who will look after it 😉 This might just be a general personality trait than an autistic trait though.