The crossword solution for the term 'Bygone G.M. Cars' is GEOS. GEOS was a subcompact car produced by General Motors from 1985 to 1997. It was sold in the United States, Canada, and Mexico under the Geo brand. The car was available in both three- and five-door hatchback body styles, as well as a four-door sedan. It was powered by a variety of engines, including a 1.0-liter three-cylinder and a 1.6-liter four-cylinder. The Geo Metro was the most popular model in the lineup, and it was known for its fuel efficiency and low price.