Whimsical Wireframes - Lightning fast wireframing with real-time collaboration.
Responsive Viewer - View multiple screen dimensions in one view
Invision - Prototyping and collaboration for design teams
Responsinator - Designed to test responsive websites on different devices.
Figma Map Maker - Figma plugin to generate map, supporting Google Maps, Mapbox
Multi Screen Test - Test your site at different screen resolutions & devices.