Which short term courses can I do along with B.Com?

This would depend a lot on your interest areas. There are a whole lot of short term courses that one can pursue eg: animation, graphic designing, software courses, creative writing, fitness instructor, yoga therapist, cookery, makeup artist, dress designing, painting, dancing, editing, acting, publi

If you have inclination to build professional career - start preparing for CA Entrance, CAT for entrance to MBA and similar courses for other professional careers. Think Big. Don't settle for petty courses.