The Google Keyword Planner

The keyword planner tool is one of the most used and popular keyword research tools out there.
The only reason for it being so popular is it’s free and is directly integrated with Google AdWords.
To start using this tool you need to have an AdWords account (which you can create one for free).
Features: The biggest feature of the Keyword Planner tool is the deep information it offers on Google (the largest search engine). The service is free to use.