I have seen this topic floating around booktube and figured I would share my Top 5 most purchased authors.
5. Heather Brewer
I have the complete Vladimir Tod series which is 5 books plus the Slayer Chronicles series first two books which gives me a total of 7 books by Heather.
4. Cassandra Clare
Of course I have the Mortal Instruments series and The Infernal Devices series. I am currently reading City of Fallen Angels on audio book And the only book I am missing from the Infernal Devices series is Clockwork Princess. Which means I have 8 books of Cassandra Clare.
3. Ellen Schreiber
I have the complete Vampire Kisses series and I have only not read the last one. But neither the less this means I have all 9 books in this series.
2. P.C Cast and Kristen Cast.
I have all the books in The House of Night series except the last one that was just released. I also have two of the Novellas to this series which means I have 13 books in all.
1. James Patterson
I have the first 2 books in the Witch and Wizard series. The first book in the Confessions of a Murder Suspect. All of the Maximum Ride series books plus one with a Australian cover. And the first three graphic novels to the Maximum Ride series. In total I own 16 James Patterson books.