Additional bus companies, listed as existing during additional years or decades, are mentioned in old City Directories, and in the WPA American Guide Series of state guidebooks.
Suburban and interurban bus companies listed in the Russell's Official National Motor Coach Guide, which was primarily a resource for intercity bus lines.
Allegan-Grand Rapids Bus Line (to Allegan, until 1951)
Division Avenue Bus Line - connected Grand Rapids with Cutlerville, existed in 1920's to 1950's.
Grand Rapids-Fremont Bus Line - existed in 1930's, possibly evolved to part of Decker Bus Line.
Grandville-Wyoming Transit Co. - connected Grand Rapids with Grandville, existed in 1940's, acquired in 1963 by Grand Rapids City Coach Lines.
Peacock Transit Lines - served Allendale, Eastmanville, Lamont, existed in 1950's.
True Blue - existed in 1930's.
United Suburban Lines - existed in 1930's to 1940's.