There have been many states added to India since India's creation. However, a vast majority have been divided from old states, while a few were annexed from other countries. Please inform me if a state has been missed.
Only those split from modern states.
There are 2 states who have been annexed into India. One of the nations is still a country while the the other has been wholly annexed.
Note that the states may have been divided, become Union Territories first, then states