These are some tools that I have running on my hosting provider, Bluehost. I have many more that I can put up here, but it is highly dependent on my time management skills and the versions of Python and PHP provided by Bluehost.
Quick HTML scanChecks the HTML at this URL for elements and attributes that are meaningful to search engines. Resource Expert Droid
A great tool that checks web resources and makes suggestions based on common HTTP header issues. Written by a genius who used to work at Akamai and now works at Yahoo!.
Main project page is here.