I had a set of the Peachtree packages, same as mentioned above. They were for the Epson QX10, I think they would have been specifically CP/M. Not sure if they were 'open' code though, notes I have suggest the code was compiled needing a run-time module. BRUN or BASRUN? I have ready access to the Purch Ledger part, other modules may be stored elsewhere, may need some digging, or disks may have been recycled even if I still have the manuals.
There was a PD disk with a complete MS-BAS 'General Ledger' system, I think I still have that somewhere. Not sure if that came with docs.
Bit more exotic, while I was a working programer, one of my jobs was looking after a commercial accounting system, back in the 90s However, this was coded totally in dBase III+, and compiled using Clipper. I certainly still have ALL the source code, which is not too far away from BASIC. We sold copied with most of the ledgers standard, but with bespoke modules added on as required. Stock, invoicing, etc could be totally bespoke. More so special requirements as needed. No full docs, but it's all fully stored in my head!! Still!!
Geoff