QuickNuke by Canisbos
This is a little Safari extension that lets you delete (“nuke”) any element on a web page quickly and easily. Deletions are only temporary; if you reload the page, the deleted elements will be back. It’s really only useful for removing annoying elements on pages that you visit once, or once in a great while.
To use: Point at the thing you want to remove, hold the mouse button down, press D, and release the mouse button. You can keep pressing D while the mouse button is down to remove ancestors one after another; press E to undo deletions one at a time; or press R to undo all deletions.