Yes you can get admission in Post graduate engineering course without appearing in GATE entrance exams . GATE entrance exam is not compulsory for admission in M tech for all colleges. many other reputed engineering colleges organized their own entrance exams for admission in M tech course ..

Other entrance exams are :
Bharath University Engineering Entrance Exam
BITSAT Entrance exam (BITSAT)
B.S. Abdur Rahman University Engineering Entrance Examination
Calicut University M.Tech entrance exam
DA IICT Entrance exam
Deenbandhu Chhotu Ram University of Science and Technology Murthal M.Tech Entrance exam
Dhirubhai Ambani Institute of Information and Communication Technology Entrance exam
GGSIPU Engineering CET Entrance exam
Gitam University Online Entrance Test
SRMEEESRM Engineering Entrance Examination
TANCET (Tamil Nadu Common Entrance Test)
University of Petroleum and Energy studies, Dehradun UPES-SEAT Engineering Entrance Test
Engineering Entrance Exam
VEL Technical University Chennai All India Engineering Entrance Examination

International Institute of Information Technology (IIIT) Bhubaneswar M.Tech Entrance exam
LNM Institute of Information Technology, Jaipur - M.Tech Entrance exam
Manipal Institute of Technology, Karnataka
Motilal Nehru National Institute of Technology, Allahabad
National Institute of Technical Teachers Training and Research, Chandigarh - Master of Engineering Entrance exam
North Eastern Regional Institute of Science and Technology (NERIST) entrance examination
Post Graduate Common Entrance Test (PGCET) Karnataka
Post-Graduate Engineering Common Entrance Test (PGECET)
PTU CET