To prepare for entrance exams, the best books depend on which exam you are writing. Please tell me the name of the entrance exam (like NEET, JEE, CUET, AIIMS, BITSAT, etc.), so I can tell you the best books for that specific exam.

But in general, here are some common good books for popular subjects:

Physics
NCERT Physics (Class 11 and 12)
Concepts of Physics by H.C. Verma
DC Pandey Series

Chemistry
NCERT Chemistry (Class 11 and 12)
Physical Chemistry by O.P. Tandon
Organic Chemistry by Morrison and Boyd

Biology (for NEET)
NCERT Biology (Class 11 and 12)
Trueman’s Biology
Objective Biology by Dinesh

Mathematics (for JEE)
NCERT Mathematics
RD Sharma
Cengage Maths Series
Objective Mathematics by R.D. Sharma or Arihant

English (for CUET, CLAT, etc.)
Wren and Martin
Word Power Made Easy by Norman Lewis

Please tell me your exam name so I can give the correct book list for that exam.