Usually the best colleges for Bachelor of Technology in Mechanical Engieneering are the Indian Institutes of Technologies and the National Institute of Technologies. Some of the top IITs and NITs provide innumerable benefits for ME students. Some of these colleges are:

IIT Bombay
IIT Delhi
IIT Bhilai
IIT Kharagpur
IIT Kanpur

NIT Trichy
NIT Surathkal
NIT Allahabad

You can also use our college predictor to see your chances in all the colleges:
https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer

Hope I have answered your question. All the best!