Typing or Pasting the Live URL (or Staging URL) from a Tridion site into a textbox in the GUI Dashboard will take us to that Page in Tridion and Open it. For example, pasting http://www.sdl.com would open the Tridion Index Page.
Also, possibly showing all Component Presentations on the Page, including the content of each Component Presentation, in 1 screen. This allows me to find content within the text of a Component Presentation and then open it.
In a recent project it was common for some Pages to contain around 50 Component Presentations. Essentially, it was a tabs page, so with 4 tabs it was like having 4 Pages of content on 1 Page. I wrote a custom Page to do this reverse lookup (using Core Service) and also show all the content on the Page, saving a lot of time to find the Page and content on the Page.