Here is a list of books that is relevant to UPSC CSE. This list has been made to give preference to the students who are preparing for the IAS examination. The Amazon link has been provided along with each book where you can check the price as well as buy it online.
This list includes both NCERT Books as well as non-NCERT Books relevant for UPSC
Indian Polity by M. Laxmikant
INDIA: PHYSICAL ENVIRONMENT
Themes in Indian History Part I, II, III. Class XII
Indian Economy By Dutt and Sundram
NCERT Books are good to grab the concept and very useful for the beginners. But NCERT books are not sufficient in all the subjects. To complete the syllabus and have a better understanding of the subject matter you will have to go for standard books.
You can buy these books either offline or online (From Amazon and Flipkart)