There is no universal lid that fits all makes, models and sizes of slow cookers. As of 2015, Sears, Marbeck Appliance Parts and The Parts Biz offer replacement lids for some brands, including Hamilton Beach, Proctor Silex and Rival.
To find an appropriate match, it is important to know the model number and volume of the slow cooker when choosing a replacement lid. In cases in which the lids are not manufactured to fit a specific brand, measurements are provided to help determine if the toppers fit particular units. Marbeck Appliance Parts also offers replacement lid knobs if the handle is broken off but the lid is otherwise intact.