A quick and dirty, not yet done Python 3 script to find duplicates.
I thought I might not have that many and that I could just delete the duplicates through the API, but alas, there are many duplicates and I don't have the time to go throuh everthing and figure out what I uploaded 4 years ago so I just bought another 100GB storage....
The script does not delete any files. It just checks for duplicates. Comments are scarce as I did not intend to commit it.
Also, there is not reference to file deletions in Google Drive API v3, only in V2. The deletion code for V2 is in here (commented out). Test it out if you wish.