Here is a great online tool that I found that you might like mouser. It lets you make a custom button for Firefox out of anything that can be loaded in the firefox url bar (including links and javascript). You can use your own icons and even redistribute the file if you like. I have a few that I made and use regularly. It works great.
http://codefisher.org/toolbar_button/link-button-makerI found that the following site has many useful bookmarklets.
https://www.squarefree.com/bookmarklets/Specifically the url navigation ones like
Up, Top, Increment, Decrement,
A few other fun bookmarklets are the ones for
vozme.com, and
TinEye