Hey shruchi, Check out this list
http://seomizeme.com/social_list.php?type=sbl
Not sure all are working or not, also you will find list of article directories, dofollow blog directories & web directories.
Personal Tip: Social bookmarking is a very powerful tool to drive traffic, but its useful only when people will view them. Submitting to social bookmarking sites cannot drive you the expected traffic. You need to find some ways to get people there on your submitted links.