Subject wise NCERT Textbooks of class 11 and 12 are best for basic preparation. Apart from NCERTs, you can prepare and practice from Concepts of Physics by HC Verma, Aptitude Test Problems by Krotov. For chemistry, A Textbook of Organic Chemistry for IITJEE by RK gupta and IIT Chemistry by OP Aggarwal. IIT Mathematics by RD sharma and Higher Algebra by Hall and Knight- these two books are best for preparation. KN Bhatia's Elementary biology for Class 12.