Hi Amruth,
The best books for IIT preparation are

Physics

Concepts of physics - HC varma
Understanding Physics-DC pandey
Practice book for physics-DC pandey
Problems in general Physics-I.E Irodov
Apptitude Test,problems in physics- Krotov
Feyman lectures on physics-R.P Feyman

Chemistry

Chemistry NCERT text book-NCERT
Problems in Physical chemistry for JEE- Narendra Avasti
Organic chemistry-Morrison &Boyd
Consise inorganic chemistry-J.D Lee
Inorganic chemistry -O.P Tandon
Organic chemistry-Solomons
Organic chemistry-Bhahal&Bhal
Organic chemisty-Arihant prakashan
Physical chemistry-O.P Tandon
Numerical chemistry-R.C Mukharjee

Mathmatics

Trigonometry-S.L Loney
Coordunate Geometry-S.L loney
Higher Algebra-Hall knight
Maths X1&X2- R.D sharma
Comprehensive Mathmatics for JEE-Mc graw Hill publication.
Problems plus in IIT Mathmatics-A das Gupta
Cenage Maths(5 books)-G Tiwani
Hope you get it.Thank you

IIT is not an easy task to crack it , we need to be ready to do the good and perfect for it ., so for that we need to refer the best books to study . I can help you to suggest the reference books for IIT preparation

Physics :

1) To study the concepts of physics you need to prefer for the H. C. Verma

2)Practice for physics on JEE mains , advance and for understanding physics you need to choose the D. C. Pandey

3)For problems in general physics , I think I. E. Irodov is the best

Mathematics :

1)Firstly you should prefer the Cengage by G. Tiwani

2)For JEE Advance on comprehensive mathematics by Tata McGraw Hill publications

3)For IIT JEE Arihant Problem Book in Mathematics by SK Goyal

Chemistry :

1)For theory purpose you need refer the NCERT Textbook

2)Morrison and Boyd for Organic Chemistry

3)For Inorganic Chemistry you need to refer the J. D.Lee book

Hope the above mentioned books will help the most to crack the exam.

All the best