Responsive Viewer - View multiple screen dimensions in one view
Aseprite - Aseprite is an art program dedicated to the creation of pixel art.
Responsive Website Test - Test any website on desktop, mobile, and tablet
Pixel Studio - The Pixel Art Is Always Fun
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.
Pixel Art to CSS - Draw and animate pixel art, export the results to CSS