People in database, datamining, data visualizations and business intelligence require datasets (sets of data) to implement, run and test their algorithms. There are a lot of resources on the internet where you can get synthetic and real datasets for free. Some of the datasets can be benchmark datasets for testing algorithm performance with industry standards. Here I am documenting some of the free resources on the internet that will help you out in your data search for academics and industry needs. I will try to keep this list updated overtime.
P.S. : Before using any of below mentioned datasets please read their respective usage policies.