Free Search Tool Bars:

• Google Tool Bar
• Yahoo Tool Bar
• Alexa Tool Bar
• MSN Tool Bar

Alternative Web Browser

• Fire Fox
• SEO for Fire Fox

 Basic Search Engine Search Commands:

• Link:www.domain.com – queries backlinks related to that specific URL
• Linkdomain:www.domain.com – queries all backlinks related to pages within the URL
• Related:www.domain.com – queries sites related to that specific URL
• Cache: Show the cached snapshot of a page
• Info: Find one specific URL in the search database
• Define: Show Google's glossary definition for a term
• Stocks: Show American stockmarket information for a given ticker symbol
• Site: Restrict a search to a single site
• Allintitle: Restrict a search so that all the keywords must appear in the title
• Intitle: Restrict a search so that some of the keywords must appear in the title
• Allintext: Restrict a search so that all of the keywords must appear in the body text
• Allinurl: Restrict a search so that all of the keywords must appear in the page address
• Inurl: Restrict a search so that some keywords must appear in the page address

Google Data Center Checker - Checks your ranking across the Google network.
Unique C Block Backlinks Checker
Reverse IP DNS Tool Checker - Lists all the sites listed on the same IP address.
Bulk IP Tool C Class Checker - Nails Duplicate content IP's and Subnets.
Google TouchGraph - makes it easy to visualize relationships between related websites.

SEO Glossary of words by Aaron Wall
The Key-Word Generator by Aaron Wall
Track the history of websites

Xenu Link Sleuth– finds broken links on your site.
Meta Tag Generator by Aaron Wall – helps you create the code for your page title and meta tags