Originally Posted by mgtarheels

Keyword Density Checker / Keyword Extractor
* Keyword Rich Domain Finder
* Keyword Suggestion Generator
* Multiple Keyword/Search Engine Position/ Search Engine Position Checker
* Bing/MSN Live/Yahoo Indexed Pages Checker
* Robots.txt Checker
* Site Spider Viewer /Site Spider View
* Alexa Traffic Rank Checker
* Compete Ranking Checker/Compete Statistics Checker
* PageHeat Checker
* PageRank Checker( Google)
* HTTP Header Extractor/HTTP Header Viewer
* Meta Tag Extractor/Meta-Tag Generator
* IP Address Forward/Reverse Checker/Lookup
* CSS Validator/HTML Markup Validator
* Domain Whois Retriever
* HTML Encrypter
* Website speed/ Webpage Size Checker
* Delicious,Digg,Twitter Link Finder

Already exist.

Not sure if the others do or not, but I know for a fact the ones above do exist.