Oh, Medea, in my experience, some of them do. Yes, true, all of them sell a mixed bunch of all sorts of things, and one has to just try them out.
Yet what they will accept from donors is filtered by the staff's perception of what is re-sellable, and perhaps their skills in repairing items, or by the number of staff members and the available floorspace and rent.
(near the tram stop Morgental) sells, amongst other things, lost-and-found objects from public transport, so it has a lot of the things that so easily get left behind while travelling: jackets, hats, scarves, gloves, spectacles (great for getting a good frame, and having one's one lenses put in), brief-cases and suit-cases, backpacks, walking-sticks, sports bags and sometimes sports gear. Fundsachenverkauf even has staff who check electronic devices for defects, clear the data, and get them ready for re-sale.
For example, Brockiland http://www.brockiland.ch/
(near the bus stop Manesseplatz, Zürich) stocks quite a lot of half-used chemical products, both for building and home repairs (paint, oil, solvents) and cosmetics (soap, shampoo) and cleaning agents... while many other brockis wouldn't keep that stuff. Great if you're just wanting to do a small do-it-yourself project. Ditto tools.
Brockiland also seems to accept quite a lot of things which would be classified as too old-fashioned in other brockis (I don't mean furniture) but clothing from the 60s and 70s, hand-make wicker baskets, wooden trinket-boxes. They also do a surprising stationery department, as long as you are looking for materials you can use, and not expecting the latest, greatest shiny giftpacks. They also do electrical (but seldom electronic) goods. They tend to sell smaller rather than larger items of furniture.
For larger furniture, as well as for olde-worlde collectable biscuit boxes or candle-stick-holders (deco) try the Arche, near the bus stop Luggwegstrasse: http://www.archezuerich.ch/
The Brockenhaus http://www.zuercher-brockenhaus.ch/
, as its website presentation shows, prizes itself in being more up-market, with genuine trouvailles, especially period furniture and fancier clothing.
Brockito near the bus-stop Chaletweg https://www.stadt-zuerich.ch/aoz/de/...ockenhaus.html
has a surprising haberdashery section. Also a staff member who is a specialist in hand-knotten carpets and, sometimes, staff who can clean these properly before re-sale. Also large furniture.
Emmaus in Dübendorf http://www.emmaus-zuerich.ch/
is well worth a visit for special crockery and glass-ware. And lamps. And furniture.
at the bus-stop Zehntenhausplatz, Zürich, has a book section kept very well classified by an impassioned bibliophile who, on special request, may even try to find specific out-of-print books. They also do furniture.
And near Hiob is Wehntaler Brock near the bus-stop Glaubtenstrasse, Zürich, which is piled high with what, at first, looks like all sorts of apparent cheap junk, but great if you want a plastic crate, a folding chair, a quick solution for curtains, and all at really fair prices, made on the spot by the very friendly owner.