Hello,

As per your jee mains rank you won't get NIT's and IIIT's.

Apart from this, you can easily get governments colleges in different states.

So check the link below 

https://engineering.careers360.com/jee-main-college-predictor

Hello Shivam with 20 k rank you may obtain admissions at NIT Patna,NIT durgapur,NIT Pondicherry.

It lso depends on the course or degree that you are aiming to pursue.With this rank you are most likely to get a seat.

Otherwise you can also apply to colleges like BIT mesra,Thapar University ,Anna University.

These colleges look at only board scores or JEE mains scores.

Dear aspirant your reserved category rank is not good enough to get a seat in nit or iiit or gftis or any other government colleges. Your Board results are good enough. Try for other government exams like wbjee and comedk. Or take admission in private colleges