if i get around 2000 rank in jee main 2020 in which good colleges and branches can i get admitted to??

A rank of 2000 is very good and can assure a seat in any top NIT or IIIT.

Getting Computer Science engineering in NIT Trichy will be difficult with this rank. However you have bright chances of getting in any branch in NIT Warangal, Surathkal and Allahabad.

If you are very interested in CSE, then you also have a chance of getting in IIIT Bangalore and IIIT Delhi, which provide excellent opportunities to their students.

You can go through the below given link to check the rank cut-offs of different colleges and branches.

https://josaa.nic.in/webinfocms/Handler/FileHandler.ashx?i=File&ii=177&iii=Y

Your chanses are really high of getting into an old NIT nit but you may not get your desired branch if you are a General candidate but it would be easy for you to get into computer science or information technology for Electrical if you are from any reserved category as 2000 is a a good rank. Else you can use career 360 college predictor link is given below.
http://www.engineering.careers360.com/jee-main-college-predictor