I’m currently taking my coaching from Dhyeya IAS which is going well. I was also searching for this but after researching I found the top 10 books referred by toppers to clear IAS preliminary exam which will help you and me.
1) Indian Polity for Civil Services Examinations by M. Laxmikanth (Polity)
2) Oxford School Atlas by Oxford Publishers. (Geography)
3) Indian Art and Culture by Nitin Singhania. (Culture)
4) Economic Survey by the Ministry of Finance. (Economy)
5) Certificate Physical and Human Geography by Goh Cheng Leong. (Geography)
6) A Brief History of Modern India by Rajiv Ahir (Modern India)
7) General Studies Paper 2 Manual by MHE (CSAT)
8) Indian Economy by Ramesh Singh. (Economy)
9) India Year Book (Current Affairs)
10) NCERT Books
Resource: https://www.clearias.com/10-books-referred-by-toppers-to-clear-ias-preliminary-exam/