Superkey 

Superkey is a keyboard utility with a twist: it can recognize text across your entire screen (using Apple’s hardware-accelerated OCR APIs) and allow you to move your mouse (and switch windows) by typing the text you see at your desired location:

This is downright magical, and surprisingly intuitive if you map it to Caps Lock

It is a surprisingly effective alternative to and for quickly switching between windows and has the advantage of working with anything: windows, tabs, documents, etc. I have been using it with Windows inside a Parallels VM and remote desktop sessions, and the only effective constraints seem to be the size of the target text (which is an acceptable tradeoff).