Responsive Design View Presets in Firefox for Web Development. http://sridharkatakam.com/responsive-design-view-presets-firefox-web-development/

devtools.responsiveUI.presets

[{"key":"1920 x 1080","name":"Nexus 5 Landscape","width":1920,"height":1080},
{"key":"1080 x 1920","name":"Nexus 5 Portrait","width":1080,"height":1920},
{"key":"1024 x 768","name":"iPad Landscape","width":1024,"height":768},
{"key":"768 x 1024","name":"iPad Portrait","width":768,"height":1024},
{"key":"736 x 414","name":"iPhone 6 Plus Landscape","width":736,"height":414},
{"key":"414 x 736","name":"iPhone 6 Plus Portrait","width":414,"height":736},
{"key":"667 x 375","name":"iPhone 6 Landscape","width":667,"height":375},
{"key":"375 x 667","name":"iPhone 6 Portrait","width":375,"height":667},
{"key":"568 x 320","name":"iPhone 5/S/C Landscape","width":568,"height":320},
{"key":"320 x 568","name":"iPhone 5/S/C Portrait","width":320,"height":568},
{"key":"480 x 320","name":"iPhone 4/S Landscape","width":480,"height":320},
{"key":"320 x 480","name":"iPhone 4/S Portrait","width":320,"height":480},
{"key":"1920 x 900","name":"Wide Screens","width":1920,"height":900}]

up

I've added some Android ones at https://gist.github.com/acarrick/32e6c694e388b4550a469da27b53cd53