1.Google Adwords:关键词规划师
https://ads.google.com
2. Adword & SEO Keyword Permutation Generator
http://seo.danzambonini.com
3. Google Correlate
https://www.google.com/trends/correlate
4. Keyword In
http://keywordin.com
5. Ubersuggest
https://neipatel.com/ubersuggest
6. Wordtracker Scout
https://www.wordtracker.com/scout
7. WordStream
https://www.wordstream.com
8. SEO Chat --Suggestion Keyword Finder
http://tools.seochat.com/tools/related-eyword-tool/
9. Google 搜索下拉框以及相关推荐
10. Keyword.io
https://www.keyword.io/
11. KWFinder
https://kwfinder.com
12. Keywordtooldominator
https://www.keywordtooldominator.com