I cannot share you the links of question papers of AP ECET since its against our laws of careers360. You can google and get question papers from there. But rather, I'll guide you with the book knoweldege that I can...
For physics, you can go for HC VERMA, DC PANDEY OR concepts of physics volume 1 and volume 2. For chemistry, you can go with Arihant or GRB and for Maths you can get Marvel or Arihant again. Arihant Publications also has some sample papers, mock tests along with previous years question papers, so if you want you can even buy that.
Refer to our site for getting a detailed information about the AP ECET exam.. https://engineering.careers360.com/exams/ap-ecet
Best wishes. Thank you.