Dear Aspirant,

There is nothing as OBC Score/ open score in JEE Mains. There are OBC Ranks, Open Ranks meaning category wise ranks.NTA  Prepares a separate rank list category wise. Now coming to score required -

Other than NITs some good colleges that accept JEE Mains score are:

IIITs, Netaji Subhas University of Technology (NSUT),IIEST, IISc ,etc....

Now you can check this analysis of Marks VS Rank VS Percentile :

https://engineering.careers360.com/articles/jee-main-marks-vs-percentile

A score of 110+ in JEE Mains will help fetch 96+percentile which would help get IIITs, NSUT and other colleges.

As you go up the percentile  there are more better options like IIIT Hyderabad IISc Bangalore,these require a very high percentile.(99.8+)

Also you can check all the  previous year  official cutoffs(closing ranks) for colleges through JEE Mains on JOSAA Website:

https://josaa.nic.in/Result/Result/currentorcr.aspx

List of colleges accepting JEE Mains Score :

https://engineering.careers360.com/colleges/list-of-engineering-colleges-in-india-accepting-jee-main

Hope this helps.