which are the best books for jee mains?

Firstly I would suggest you to prefer NCERT books to build your concept then prefer other books.

Physics : Concept of Physics by H.C. Verma , Fundamentals of Physics by DC Pandey , Problems in Physics by I.E. Irodov

Chemistry : Numerical problems in Chemistry by P. Bahadur, Organic Chemistry by O.P. Tandon.

Mathematics : Mathematics by R.D. Sharma, Algebra by Hall & Knight

Good Luck!

Below are the best books for JEE Main you can check

Physics

HC Verma – Concepts of Physics (Part I)
HC Verma – Concepts of Physics (Part II)
IIT JEE Physics – DC Pandey
Problems in General Physics – I.E. Irodov
Physics for IIT-JEE – Resnick, Halliday, Walker.
Problems in Physics – S.S. Krotov

Chemistry

Organic Chemistry – Morrison Boyd
Organic Chemistry – O.P Tandon.
Modern Approach to Chemical Calculations – R.C. Mukherjee
Numerical Chemistry – P. Bahadur
Concise Inorganic Chemistry – J.D. Lee

Mathematics

IIT Mathematics – M.L. Khanna
Differential Calculus – A Das Gupta
Class XI & XII Mathematics – R.D. Sharma.
Trigonometry, Geometry Books – S.L. Loney.
Problems in Calculus of One Variable – I.A. Maron
Higher Algebra- Hall and Knight