Hey there
As I have searched there are no other counsellings other than JOSSA available for admission in premier National institutes of Technology and Indian Institute of Technology. JOSAA counselling is done after clearing JEE main exam.
For more details related to this click on below link:
https://www.google.com/url?sa=t&source=web&rct=j&url=https://engineering.careers360.com/articles/josaa/amp&ved=2ahUKEwidjoD29ZzzAhWQfn0KHdoDBDkQFnoECAoQAg&usg=AOvVaw2FP7dykFcEyfwr-CCvN6Kz&cf=1
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