SearchVolume

Query the association words of multiple foreign websites at once

It's a powerful keyword research tool that I've used and am very impressed with. 

Keyword Planner helps you research keywords for your Search campaigns. You can use this free tool to discover new keywords related to your business.

A useful tool to indentify terms you should be using with yor blog posts

It's a bit like an introduction to a word in a dictionary. I usually use this tool to write articles that are semantically related. For example, if the topic of an article is about weight loss, then I actually need to add "exercise" to the article. The words "oatmeal" and "calories" help search engines to understand the content of this article

A keyword research tool that generates thousands of profitable keywords with monthly search volume, CPC & competition