I don’t think there are active threads that discuss about Balance Sheet / Financial Statement Analysis. There are a few, but they are either inactive or dead. You could just search for ‘Balance Sheet’ in the search bar.
Personally, I always found the following useful:
- Romancing the Balance Sheet by Anil Lamba
- How Warren Buffet Interprets Financial Statements by Old School Value
- Ratio Analysis by WallStreetMojo
- A Primer on Financial Statement Analysis by Aswath Damodaran
Any standard textbook on Accounting/Financial Statements could be useful as well, but they would contain a lot of stuff unnecessary for investing purposes.