1. Google Webmaster Tools
2. Google Analytics
3. SEMrush, SearchMetrics Essentials, Moz Keyword Difficulty Tool (for international searching)
you can use SEMrush and SearchMetrics to analyze your current market and main competitors.
To find out the popular search engines in your target country, you can use Statcounter or Alexa. After that, use their analytic tools to analyze traffic, e.g, Google Adword in Western countries, Yandex Keyword Statistics in Russia or Baidu Index in China.
4. Ubersuggest, SEOchat Suggestion Keyword Finder (ideas for your international keyword)
These tools suggest keywords to add to your main keyword. You can choose multiple languages and countries.
Please contribute or correct my mistakes.
