For better understanding please read this post:

https://medium.com/@amangoeliitb/build-a-solid-career-in-tech-without-a-cs-major-39cdef86013

Hello Aspirant.

Its great to learn from you that you are intrested in doing certification courses as now in this time of competition, something extra is always preferred. 

There can be alot of options in which you can do certification.

But if you have interest in CSE you can go with different Programming languages like python, java, ruby etc etc. 

Not only just programming languages but subjects like Data structures, DBMS, Algorithms etc 

Or you can do one on Machine leaning, AI- Artificial Intelligence, Cloud computing, AWS etc. As these in very demand now.

All the Best. 

There are a lots of certification courses that you can opt as for example there are a lots of trending technology like hadoop cloud computing web designing app development . You can go for Oracle certification or for redhat certification courses that is also good for a cse engineers

A btech candidate can learn a lot of ongoing technologies in computer science which can give him a proper job or which can settle his career .
A few important certification are as follows:
1. Python
2.ORACLE
3.Oracle certified java programmer
4. Nptel courses
5.machine learning.
6.web development
And few more courses which can be searched online.