Yes there are a lot of colleges that give admission based off of your 12th class merit for example:

1. Tamil Nadu Engineering Admissions aka TNEA – Conducted byAnna University, TNEA is as the name suggests based on the marks obtained in the qualifying exam i.e. 10+2.
2. Rajasthan Engineering Admission Process or REAP – Conducted by Rajasthan Technical University (RTU) Kota, admission to B.Tech programmes are on the basis of JEE Main scores or class 12th board percentile with preference being given to JEE Main candidates.

for more details check out : https://engineering.careers360.com/articles/btech-admissions-on-basis-of-class-12th

There are also colleges which conduct their own exams for admissions such as VIT and SRM or BITS.

for more details on these visit : https://engineering.careers360.com/exams