Here are some of the past year toppers of UPSC CSE Law optional subject:
Year 2022: Kritika Goyal (AIR 14)
Year 2021: Jaspinder Singh (AIR 33), Avinash Rao (AIR 31), Kaanchi Singhal (AIR 213)
Year 2020: Varuna Agrawal (AIR 38), Vasu Jain (AIR 67), Aayush Gupta (AIR 74), Anmol Mittal (AIR 91), Nirja Shah (AIR 213), Ishan Gupta (AIR 215), Aditya Mahar (AIR 668)
Year 2019: Ankita Agarwal (AIR 4), Ayush Rai (AIR 12), Akash Gupta (AIR 13), Pawan Goyal (AIR 17), Shubham Garg (AIR 22), Aditya Raj (AIR 25), Vaibhav Thakur (AIR 36), Manish Kumar (AIR 41), Shivangi Jain (AIR 43), Harshit Sharma (AIR 44)
Year 2018: Pratiksha Mishra (AIR 1), Ayush Upadhyay (AIR 2), Pranjal Shukla (AIR 3), Anshul Agarwal (AIR 5), Akash Gupta (AIR 9), Rishabh Jain (AIR 10), Sanket Kumar (AIR 11), Ashish Kumar (AIR 13), Siddharth Pandey (AIR 14), Abhishek Gupta (AIR 15)
As you can see, there have been a number of high-ranking toppers in recent years who have chosen Law as their optional subject. This shows that it is a viable option for those who are looking to do well in the UPSC CSE exam.