I had an idea a couple of weeks ago -- vintage data.
Data that you could guarantee was not generated by AI. Stuff like scans of old microfiche archives, scans of rare but unpopular books found in old boxes and attics. Things like that.
Free startup idea! Go to garage sales and look for boxes of books that maybe have never been digitized.
Just be careful that the entire training set doesn't have the moral values of 100 years ago!