Why you may ask ??
Carve the mark
Carve the Mark shares some of the great elements of Throne of Glass - Strong characters, characters with more than human abilities and hidden plans that keep you turning the pages way past bedtime - but its set in a totally different genre so there is a whole new amazing 'planet' to discover . With strong protagonists, an evil prince and an underground rebellion I don't know what more you need but just encase there is also inter-planet fighting, amazing airships and its set in space .... come on!
The Lost Prince
Now full honesty this book just reminds me of Aedion :) So it's more of a 'what to read after you finish book 5' . Following unavoidable events Ethan the Main character is forced to hide out in the magical world that he has spent years trying to avoid and hes not alone.. Mackenzie St.James, the cute reporter from the school paper, is now court up in the dangerous world not meant for mortals and with a destiny that wont leave him alone and a cute girl that refuses to return to safety Ethan's got his work cut out for him if their every going to get home. The Lost Prince is a great book for everyone
The Demon king
Okay take a minute with me and imagine two medieval schools side by side and at one you study how to control high magic and at the other you learn how to fight for the best armies ... Now if you haven't gone there already imagine the Throne of Glass characters a few years younger (or in some cases a few hundred years younger) attending those schools !! The Demon king trilogy is sooo good and I'm not doing it justice with this explanation but seriously this book goes toe to toe with Throne of Glass, its full of magic and action , with two very solid main characters and two intricate stories . You'll find this hard to put down and with each book having no less then 500 pages they look daunting but they are super easier to read and the language is not overly intricate so you'll find yourself finishing and grabbing for the next one faster then you think .
So with my 'no spoilers' rule this one is hard to explain why is a 'read next' but basically for fans of the "Throne of Glass queen" and her "warrior prince" (if you get my drift 'cough cough') then read this! I loved it , the focus on just the two blood types was interesting and meant the author could really build the world and characters . It would be a great book to read if you enjoyed Carve the Mark too. Basically a bit of the throne of glass world but the character building of Carve the Mark and hey I'm not upset with that :P .