Most vintage Pyrex hunters can spot a Butterprint bowl across a thrift store. Collectors have named it "Mod Kitchen," but Pyrex never even bothered to give it an official name. But that wasn't the name; it was just a label the company used for dozens of unrelated promotional patterns over the years. Mod Kitchen casseroles without their warmers and lids are still valued by Pyrex collectors, selling for around $15 in good condition. Since Pyrex is still the vintage dishware brand you should always snag, it's worth memorizing the patterns of promotional pieces like Mod Kitchen.