Have you seen a product and wondered who were the other companies in that business? Or searched for stocks related to a particular keyword?
Tradestream.in's Watchlist Builder does exactly that. Search for one or more keywords and find all the companies related to it. Type in one or more words, and select whether you're looking for all or any of the words. When you've found the stocks, select the ones you'd like to import with the checkboxes next to the price, and hit Export.
This is still evolving and it will get better with time, but is reasonably accurate. If you can't find anything for a particular word, try using related or similar words. Here are some interesting keywords we tried-
Biotech companies working on genome sequencing and related activities
With security threats on the rise, some companies working on cyber security
With self driving cars, drones and unmanned robots, radar and lidar are key areas, we searched for radar and found these-