If 51k is your EWS category rank, it will be quite difficult to get seat in NITs, IIITs or GFTIs. You may opt for private engineering colleges. Following are some best private engineering colleges in India.

1. BITS Pilani
2. VIT Vellore
3. SRM University
4. KIIT
5. Thapar University
6. Manipal Institute of Technology
7. Lovely Professional University
8. Chandigarh University
9. RV College of Engineering
10. BITS Mesra
11. DA - IICT
12. KJ Somaiya College of Engineering

However you have a chance to get a list of prescribed colleges against your rank. You just need to use JEE MAIN COLLEGE PREDICTOR. Click the link below, put necessary information and get result instantly.

https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer

All the best