Can you suggest some engineering colleges in Mumbai where I can get admission with more than 50% in 12th grade?

With more than 50% in your 12th grade, you can consider engineering colleges in Mumbai like VJTI (Veermata Jijabai Technological Institute), Sardar Patel Institute of Technology (SPIT), and K J Somaiya Institute of Technology. You'll likely need to focus on entrance exams like MHT-CET.