Gagaga文庫排行

"Gagaga文庫" is not a term I'm familiar with, and it doesn't seem to be a standard ranking system or a well-known collection of books. It could be a made-up term or a local/regional ranking system that is not widely recognized.

If you're looking for book rankings or bestseller lists, there are more common sources and platforms you can check, such as:

1. Amazon Best Sellers
2. New York Times Best Sellers
3. USA Today Best-Selling Books
4. Publishers Weekly Bestsellers
5. Goodreads Choice Awards
6. Book of the Month Club selections
7. National Book Awards
8. Man Booker Prize winners
9. Nobel Prize in Literature recipients
10. Hugo Award winners for Best Novel

These lists can give you a good idea of the most popular or critically acclaimed books across various genres. If you're looking for a specific genre or type of book, you can also find specialized rankings and recommendations.