Unamo Design’s 3Moods has detachable components and magnetic straps that allow it to transform into various pieces of furniture. You can turn one or both halves into a couch, a lounge chair, a table with two chairs, and more.
Made by Lithuanian shop Life is Short, the Rocking Couch is a flat pack cardboard couch. It weighs just ~20lb but can hold up to ~330lb. You can assemble it in just two minutes without tools or glue. Lasts up to two years.