Louis L'Amour as an author.
As a teenager I was very fond of LL as an author of Westerns- I read all I could find. "Flint", "Fallon", "Hondo", "The Daybreakers", "Catlow", "Sackett", "Reilly's Luck" and "Lando" were among my favorites. After reading probably a hundred of these books I moved on to something else and several decades passed. About 10 years ago I revisited LL's body of work, and I made an interesting discovery- LL didn't actually write 200 or so books. He wrote about 10 or 15 books- OVER AND OVER AGAIN. The characters are cookie-cutter similar, the plots are direct knock-offs of each other- it's hard to believe. The reason the above-named books were my favorites is a simple one- they are among the truely original works that LL later cloned and resold dozens of times. I conclude that LL is very good where he bothers to be original, but when you read the third or forth retelling of the same story,it really starts to wear on you.
Just my .02 worth.