Below is a list of my favorite tools to carry out keyword research:
Storybase is a keyword analysis tool. Starting from a single keyword the tool will show you the following information:
Demographic data (age & gender of the searchers).
Most popular questions related to your query
Phrases related to the keyword
Related keywords and phrases
Number of searches per month
The tool currently covers the US,UK & Danish markets and is free for a limited amount of searches.
Enter a word or phrase into this free tool and it will show search query statistics for searches on Yandex the Russian search engine. The figures next to each query in the results are a provisional forecast for the number of impressions a month for a given keyword or phrase.
RankTank Infinite Suggest
looks at keywords and their associated nouns/adverbs/all
This free tool extracts searches from Google Suggest SERP data. You can set view mode (linear, table, tree), scan mode (loop, alfanum, alfanuminvert, correlate) or by Google domain (.com, .it, .de) and language (en, it, de).
Starting with one keyword this tool will scrape Google of the suggestions connected to that word. What is very useful about this tool is that you can keep adding words to the list. Also, each suggestion contains a link to the SEMRush tool for further analysis.
Think with Google
It allows you to search for products and splits popularity of product by demographic, location, device etc. also showing volume to some degree. Only US at the moment but worth checking out as has some interesting data points.
Google Adwords AdPreview tool
For viewing SERPS for different locations/languages/devices/domains – it’s been really useful when looking at where clients rank on a localised scale.
Free tool (up to 700 keywords at a time), to get keyword ideas. Just enter your main search queries or a URL, select the Google market.
Voice search tools
With the rise in voice activated searching via personal assistants like Amazon’s Echo (aka Alexa), Google Home (a direct competitor of the Echo), Siri and Cortana, it is essential to use online tools to work out how users search in a different way using this method.
Input a keyword and visualize keyword research content ideas that users could be using when carrying out searches via personal assistants. The free tool will show you various questions and prepositions connected to the your keyword. All data can be exported in .csv format for further analysis.
Free tool in Italian (but still usable for English speakers) that for a given keyword shows many metrics connected to searches for Google Italy (google.it). Metrics include; Keyword difficulty, search volume, Pages indexed in Google, average CPC, seasonal differences, latest SERPs results, overview of ranking trend of the top result, backlink competition and the adverts appearing for this query (in Google).