Well I think there are interests that tend to lead to accumulation of a lot of stuff, whether one has hoarding tendencies or not. Artwork and its supplies, crafts - especially using yarn or fabric. Books - obvious. My SO has a lifelong interest in mechanical projects, and has accumulated a lot of tools.
I also think hoarding is sometimes not as much tied to a disorder as it is to finances. If you don't have money, then you're more likely to hold onto something in case you need it later, especially if you're into creative or DIY projects, than if you know you have enough money to replace it whenever you want.
So just simply saying someone is a hoarder - it's not that cut and dried. Though I think there are mental disorders that lead to somewhat senseless hoarding. My SO was once paid to help clean out a woman's apartment after she was evicted and time had run out for her to claim her things. Oh my, the things she kept, such as scissors, old, broken, useless scissors, all over her place. Why? There was no reason we could think of. That and other kinds of things she kept led us to think she was a hoarder with no reason - except perhaps one inside her own mind. I still feel sorry for her though that she lost all that stuff that must have been important to her, for whatever reason.
All that said, I do have a lot I need to get rid of. My biggest problem is organizing it all and making DECISIONS.
Plus, a lot of it I know I can sell on-line - but I don't have a reliable car to make regular runs to the post office.