Dear applicant it totally depends on your Diploma subjects, if you have core Science subjects then apart from B.Tech you can do courses like

1. Bachelor of Pharmacy

2. Bachelor of Optometry

If you don't want to choose B.Tech you can select the above mentioned courses to get the best benefits. B.Pharm courses in many colleges welcome lateral entry students in the second year and you can pursue your higher studies. But you need to pass 10+2 to study the courses,

Good luck!!

Dear aspirant,
For admission into any undergraduate course, you need to pass the 12th class. Then you can opt for any course as lee your choice. Since you have named B. Tech the following are courses that would belong to the same background however completing 12th class is a mandate.
BCA (Bachelors of Computer Applications)
B.Sc IT (Bachelor's of Science in Information Technology)
B.Voc (Software Development)
Hope this helps