Simple = Select + Search od Diego Presno

After multiple requests, here's a port of this extension to Firefox.

This simple browser extension lets you easily add different search engines and access them from any web page.

Extension's features
- Customize: Easily add new search engines from our featured list or configure your favorites.
- Search everywhere!: Look for the same term in multiple engines simultaneously.
- Group links: Power users can organize search engines into different groups, enhancing the "Search everywhere!" feature.
- Advanced configuration: Choose where to open search results: in the same tab, a new tab, or even a new window... and a lot more!