Good topic. I am like you, I don't 'officially' collect anything (except books) but I have a penchance for anything boomerish, anything retro 50s or 60s. Right now I'm trying to find a dining room table and chairs, the old arborite (I think it was called?) ones, the ones with the big chrome legs and a chrome rim around it then the arborite (no, that isn't the name... is it formica?) top. From the 50s, you know the kind I mean. I want one. Badly.
I even bought a wringer washer awhile back, with full intentions of using it. Well, I DID use it, loved it, then it packed it in after two loads. Just try and find parts for those things. It is gone now.
So, that would be my closest thing to a collection, I think. Just retro boomer kitsch items like that.
Oh, and those little tiny birds with wire feet that you get at the craft store and stick onto the Christmas tree. I have an awful lots of those things, and cannot say no to them, so perhaps that, too, would be a collection.