If your way finds Schober (see my comment) for Coffee, Tea, Hot Chocolate, Friandises... then you can't miss Schwarzenbach... it's just 10 meters down to the main "Gasse" in the hotspot of Zürich's Niederdorf. 100 years old, in the 5th generation managed by Heinrich Schwarzenbach, perfect in it's product range, colonial, exotic, oldfashioned, you can go there to travel in spirit... or acquire some of the goodies... seems to be close to 3'000, I read.
Schwarzenbach offers whatever comes into your mind... difficult to make the point. For people visiting anyway only a glimpse is possible...Besides coffee (aks for a "Hausmischung"), tea, chocolat, you also are able to chose from dried fruits, sweets of any kind (I don't like) (I love cheese), jam, honey, oils, vinegars, spices, rice, pasta & c...
Schober uses Schwarzenbach's products... besides many tourists and local clients also visited regularly by grand chefs of top cuisines. It is most high quality.
Personally I am rather searching for interesting teas , having been a lot in Asia. Try Formosa Jade Oolong Dung Ti or their Green Tea Gyokuro.. fantastico! (well, Gyokuro is the celebration Green Tea, grown in the shade rather than with sun exposure, expensive. I also have the one offered by Globus (powder), about same price, quite difficult to get to the point which one is better...because I drink it irregularly, its used only for special occasions and I do so as well). Contrary to their recommendation to boil at 60°, would rather wait until the water is down to 45°.
Their webpage is also full of informations on products, unfortunaltely only in German: http://www.schwarzenbach.ch/
Last not least: don't be in a rush if you want to shop there! read more