I don't think my closet could get like that I would have them all set up. Now that I just bought a house and a full basement waiting to be filled with tanks.
my fishroom closet is filled with all sorts of crap like that. smaller rubbermaids, filters, heaters, anything i need, plus many many many boxes. (assorted shipment boxes i don't want to throw away.)
I have stuff laying around in the spare bedroom closet, moved stuff there from under my 135gal when I sold it, and never moved it back under the 240gal tank the replaced it. I also have small stuff in the garage. I mainly keep things in the tank stands. I had a 180gal in the garage for about a year until I built a stand for it. Now it's in the spare bedroom and has a 10gal and 20gal under it. The house we are in now (bought a couple years ago) has two areas where my two display tanks are located. Part of the reason we picked the house and that it was in the end of the court (new houses in CA don't have basements).