I want to ask about courses, certifications or something like that is useful along with PhD in chemistry for personal development and knowledge building as well as those which are helpful in future for career along with PhD ?
What is your area of research? You can do certification courses in European languages, or computer programs. If there are any training sessions on analytical instrumentation, they might be useful. For example German would be helpful if wish to pursue postdoctoral studies in Germany or Austria.
In addition to the foreign languages, u can also practice yourself in R programme and/or MATLAB or any other advanced statistical software. I have encountered many scientists specifically asking for person with knowledge in R while applying for Post Doc.