Reviewshake - Reviewshake helps you manage all your review sites from one place, automate new reviews from your customers and track review performance
PublicAPIs - Explore the largest API directory in the galaxy
Review Monitoring - Review monitoring helps restaurants and hotels aggregate their customer reviews
API List - A collective list of APIs. Build something.
Reputon - Collect, improve, manage and display Google, Facebook, Trustpilot, Yelp & Amazon reviews on Shopify merchant store, avoid negative reviews. Testimonials and feedback to boost your website SEO.
The Unsplash API - No-limits, do-what-you-want API for access to 200K+ HD pics.