Chromeの拡張だけでもこれだけあるね

Sizzy
https://chrome.google.com/webstore/detail/sizzy/nfhlbmjiiogoelaflfclodlkncbdiefo

mobile browser emulator
https://chrome.google.com/webstore/detail/mobile-browser-emulator/lbofcampnkjmiomohpbaihdcbjhbfepf

Emmet Re:view
https://chrome.google.com/webstore/detail/emmet-review/epejoicbhllgiimigokgjdoijnpaphdp

Chameleon
https://chrome.google.com/webstore/detail/chameleon/acdpiemklcfaoglpjmidpjdbhkgdoede