Hello aspirant,
The list of courses after bsc. Biotechnonogy is attatched below. But all of them are 2 year couses. And nowadays all postgraduate courses are of 2 years.
M.sc Biotechnology

M.sc Biochemistry

M.sc Botany

M.sc Zoology

M.sc Cell Biology

M.sc Molecular Biology

M.sc Bioinformtics

M.sc Agriculture

M.sc Food Technology

M.sc Animal Biotechnology

M.sc Biophysics

M.sc Computational Biology

M.sc Biostatistics

M.sc Genetics

M.sc Marine Biotech

M.sc Nano Biotechnology

M.sc Plant Biotechnology

M.sc Forensic Science