Hello,
The best mcq books for neet pg are:
Anatomy- Rajesh kaushal/raviraj
Physiology- Krishna Kumar( CRISP)
Biochemistry- Rebecca james
Make sure you have read the standard books like BD Chaurasia/Vishram Singh for anatomy, GK Pal/ AK Jain for physiology and Satyanarayan/Vasudevan for biochemistry before attempting to read mcq books.
You can also read certain topics you do not understand from the standard reference books like Grey's anatomy, Guyton/Ganong and Harper/Lippincott.
I would suggest read the textbook first then read the mcq books and solve questions.
Hope this helps.
All the best