You can still access Google Keywords if you open a Google Adwords account (you don't have to purchase an ad, just look like you are interested in doing so). Otherwise use Google Trends, although it is limiting or type in a keyword in Google and look at the "searches related to" given at the bottom. You can also use Google Autocomplete where you start typing in a keyword in the search box and Google will fill in options but it will just give you keywords that come after the main keywords, not before.
