sellerboard is an accurate profit analytics service with additional tools: follow-up mail campaigns, inventory management, reimbursements for lost & damaged stock and other FBA errors, PPC optimizer, listing change alerts and much more. All that for a competitive price, starting from $15 a month.
mention - Media monitoring made easy with Mention. Create alerts on your name, brand, competitors and be informed in real-time of any mention on the web and social networks
Helium 10 - Our software contains multiple Amazon seller tools to help you find high ranking keywords, identify trends, spy on competitors, & optimize product listings.
Dovetale - Find and work with influencers using image recognition
Jungle Scout - Amazon product research made easy.
BuzzSumo - BuzzSumo allows you to discover the most shared links and key influencers for any topic. It's free to use and you can run a search in seconds!
AMZScout - AMZScout extension will help you make a decision about picking a niche based on the actual data, not intuition.