"External Application Button" extension allows you to define customizable toolbar button and context menu items that can execute external executables by passing command-line arguments of your choice. Using this application, for instance, you can send the current page to another browser or send selected text to a text editor. It is even possible to directly send image URLs to a photo editor of your choice or send download links to an external download manager!

Note that for this application to work, there is a minimal native client that needs to be installed manually.