See first of all you should know that AIIMS examination has been scrapped from this year ie 2020. And NEET is only a centralized examination for admission to all the medical courses. AnD then Cmng to your question, then I'll suggest you NEET MTG CHAMPION book for Chemistry, Regardless and NEET CHAMPION for Physics, and NCERT reading again and again and any mcq book for practice mostly PRADEEP for biology.

And for question papers, I'll provide you with the link you can check out them there..

https://medicine.careers360.com/articles/neet-sample-paper

Best wishes. Thank you.