Wayback Machine - Browse through over 150 billion web pages archived from 1996 to a few months ago.
AppLaunchpad - Create free beautiful screenshots for App store/Google play
Archive.md - archive.is allows you to create a copy of a webpage that will always be up even if the original link is down
Placeit - Generate realistic product shots in seconds
Time Travel - Prebook rides for Uber
Smartmockups - Create stunning product mockups, easily and online.