These are some of the upcoming entrance exams for which you will be eligible if you are a 12th passing candidate:

Engineering:JEE main,JEE Advanced(for IITs,NITs,IIITs),BITSAT( Birla Institute of science and technology),VITEEE( for VIT university),SRMEEE( for SRM University), MHTCET,Maharashtra Common Entrance Test( for admission into any institutes in Maharashtra),KIITEE( for admission into Kalinga Institute of Industrial Technology, Bhubaneswar)

Architecture:NATA,JEE main paper 2( to get admission in top architectural institutes)

Medical:Only one Medical entrance exam-NEET , no separate AIIMS or JIPMER examinations.

Law: CLAT(Common Law Admission Test),LSAT(Law School Admission Test),AILET(All India Law Entrance Test),  to get admission in Nationally recognized law institutes.

All the best!!