Merchant words is very easy to use. All you do is put your keyword into their search, and they will provide you a list of all relevant keywords that are searched on amazon, and their search volume. We have used this a lot for all of our products that we sell on amazon. This gives us a comprehensive list of relevant keywords to use to optimize our listings. You can also search different amazon countries as well Review collected by and hosted on G2.com.

There is not really a way to browse different unique keywords. If you search "cooler" it will give you all the long tail keywords with "cooler" in it. Review collected by and hosted on G2.com.