This script adds a button that scrolls you back to the top of the page. It is based off a script by Numbermaniac, but is modified so the button does not cover links in the toolbar. You can view the source code here.
Hint: It's much easier if you get ScriptInstaller, then navigate to User:Danski454/goToTop.js and click "Install" at the top. To install: Copy the line below into your common.js page.
{{subst:iusc|User:Danski454/goToTop.js}}