There are so many SEO tools available in the market. Below is the list of some of them which we like the most. We are using different SEO tools during the process of search engine optimization and search engine marketing.

Broken / Dead Links Checker

http://www.dead-links.com

Keyword Research Tools

http://inventory.overture.com
http://www.wordtracker.com
http://www.digitalpoint.com/tools/suggestion
https://adwords.google.com/select/KeywordToolExternal

Keyword Density Checker

http://www.ranks.nl

Rank Checking

http://www.googlerankgins.com
http://www.seologs.com/rank-check.html

Backlinks Checking

http://www.backlinkwatch.com

Google Page Rank Checker

http://www.digpagerank.com

Google Datacenter Watch Tool

http://www.mcdar.net/dance/index.php