Additional bus companies, listed as existing during 1930's, are mentioned in the WPA American Guide Series of state guidebooks.
Alliso Bus Line - served Bloomington, Martinsville, Mooresville, Indianapolis.
Indiana Coach Lines - served Bloomington, Nashville, Columbus.
Transit Service Co. - served Camp Atterbury to Indianapolis.
Indianapolis-Crawfordsville Transit - existed in 1930's, presumably operating between their namesake cities, possibly evolved to part of Illini Swallow Lines.
Central Indiana Coach - existed in 1930's.
Del Ray - existed in 1930's.
Warsaw Bus Lines - existed in 1930's, presumably operated west to Warsaw.
Mitchell-Bedford Bus Line - no further information.