my jee main sc category rank is 20000can I found nit or iiit or gfit

Hello there,
You might get admission to colleges as follows,

Pune institute of computer technology
IIIT Pune
Vishkarma government engineering college
DTU Delhi

But getting good NITs will be quite difficult.
Here's the college predictor tool which will help you.
https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer

Hope this helps and plz use the above link to get a brief idea about what college you'll get.
Thank you.