Here you can get some useful bookmarklets. Just drag the link to your bookmarks tab!
Edit mode toggler and Title changer - might be useful for, well, editing.
Evaluator - execute some Javascript. Might not work on some sites, because it uses eval().
Google search - quickly switch to Google to look up something.
Password generator - a simple and "cryptographically insecure" password generator.
Coin - toss a coin to make up a decicion.
Wayback Machine - look up an older version of the site.
Save decompiler - for Orteil's Cookie Clicker. Might work on older versions... though then it won't show the legend.