1. Rick Riordan: I own 9 books buy him because I love his series Percy Jackson and the Olympians, Heroes of Olympus and The Kane Chronicles although I obviously don't own all of the books in these series expect Percy Jackson I plan to one day and I have loved every book of his that I have read and always look forward to reading more of his books in the future.
2. Ellen Hopkins: I own 7 books by Ellen Hopkins and I have read five of them and I have loved them all because of how she uses easy to understand poetry to tell her stories which always seem to cover heavy topics in ways that don't feel preachy. I loved all of her books that I have read but if I was to put them in order it would be Impulse, Perfect, Tricks, Tilt(mostly because of Shane), and Identical, I loved all these books and if anyone would like me to expand on my reasoning for the order I'd love to write about it because I would love to be able to talk about her books at length.
3. Ally Carter: I own 8 books by her because of my love for the Gallagher Girls and Heist Society series these are both fun series about young girls that are filled with action-adventure, friendship, humor and romance which I love all of these things and there just great fun to read.
4.Natsuki Takaya: I own 25 books by her because my favorite work of fiction of all time is the Fruits Basket manga which she has written and that happens to be 23 volumes long and I would recommend that series to everyone whether they think manga is there thing or not because it has the best story, character development and writing that I have ever encountered and I feel that everyone should read this series because of this. I also feel that everyone should read Fruits Basket because it's a series where characters have to overcome a lot of things but they are shown to be able to overcome those things even when it feels impossible and they have to overcome those things by putting in a lot of effort which I think helps to inspire people to improve themselves. Also if anyone who reads this is a fan of Fruits Basket I would love to discuss the series with you.
5. Clamp: I own 67 books by Clamp but that is no where near close to most of the books that they have written since they have tons of series that they have been writing together for the past twenty years and I have loved everything that I have read of their's so far even though some of their series are very strange. I love Cardcaptor Sakura which is a very happy story that is about love in all it's forms as well as a young girl having to capture and control magic cards, I loved Tsubasa Reservoir Chronicle which is about a group of misfits who travel across dimensions together and form a make shift family and then things get dark and sad then confusing to the point that nothing makes sense anymore. I love Tokyo Babylon even though for quite sometime it feels not much happens but when things start happening I felt like my heart was ripped out trampled on thrown through a woodchopper and then shoved back in my chest in summary the ending is completely heartbreaking in the best way possible. I love Magic Knight Rayearth which is about three young girls that have to save another world and become very close friends very quickly things don't turn out the way the expected it would. There's quite a few other series by Clamp I love but these four are my favorites and if list all their series it would take far too long but I definitely recommend their stuff if you're looking for something different.