Responsive Website Test - Test any website on desktop, mobile, and tablet
TrackDuck - Visual feedback for web design and development.
Responsive Viewer - View multiple screen dimensions in one view
Valist - Automatically created staging environments for every update with a shareable link for testing
LT Browser by Lambdatest - LT Browser is a free dev friendly browser for developers and testers. You can see mobile view of website on different screen sizes and resolution on 50+ pre installed view ports. You can build, test and debug your website faster then ever.
Usersnap - Usersnap is a customer feedback software for SaaS companies that need to constantly improve and grow their products.