I've re-uploaded some U.S. Army Reference Data publications from the U.S. Army Heritage and Education Center. I've optimized the PDFs (the originals were 100-300MB+) and labelled them a little better so hopefully they're more searchable than on the USAHEC site. These are primary source documents.
These are extremely detailed Tables of Organization and Equipment, but sometimes include other things like logistical data, missions, capabilities and other info. They often include every subunit in a division down to the personnel level.
"ST 1-100-1: Reference Data for Army Aviation" (May 1973)
Includes all divisional and non-divisional Aviation.
"ST 7-157: Infantry Reference Data, Volume 1" (FY 1975)
Includes the Infantry, Mechanized, Armored, Airmobile, and Airborne Divisions and Separate Brigades.
"ST 17-1-1: Armor Reference Data, Volume I, The Army Division" (FY 1977)
Includes the Armored, Infantry, Airmobile, and Mechanized Divisions
"ST 17-1-1 C1: Armor Reference Data, Volume I, The Army Division" (February 1978)
Change No. 1 replacing the Armored and Mechanized Division Aviation Company with an Aviation Battalion.
"ST 17-1-1 C1: Armor Reference Data, Volume I, The Army Division" (April 1979)
Includes minor TO&E changes and small unit additions.
"ST 17-1-1: Armor Reference Data, Volume II, Nondivisional Organizations" (1978-79)
Includes the Armored Cavalry Regiment, Separate Armored Brigade, Air Cavalry Combat Brigade, and Separate Armor Battalions.