These works exactly like a whiteboard would except these are not your everyday whiteboards.
Post My Pillow is an actual pillow (with marker) that you could write messages on. Available here.
Zero Waste is a city bag made from a single sheet of #2 plastic. Its pattern allows for zero cutting waste in manufacturing. Zero Waste can be used as a travel log, allowing you to record thoughts, inspirations and messages directly on the bag. Light weight, durable and machine washable, it includes a non-toxic marker that can be used to personalize Zero Waste with doodles, sketches and notes. Available here.