List of free SEO Tools:

[B]Keyword Tools[/B]
[URL="http://www.iwebtool.com/keyword_suggestion"]Keyword Suggestion Tool[/URL] by iWebTools
[URL="http://ubersuggest.org/"]UberSuggest[/URL] by Alessandro Martin
[URL="http://www.internetmarketingninjas.com/seo-tools/keyword-density/"]Keyword Density Analyzer[/URL] by IMN
[URL="https://adwords.google.com/o/KeywordTool"]Adwords Keyword Tool[/URL] by Google
[URL="http://www.seochat.com/seo-tools/keyword-cloud/"]SEO Cloud[/URL] by SEO Chat
[URL="http://www.seochat.com/seo-tools/url-rewriting/"]URL ReWriting[/URL] by SEO Chat
[URL="http://www.seochat.com/seo-tools/keyword-optimizer/"]Keyword Optimizer[/URL] by SEO Chat
[URL="http://tools.seobook.com/keyword-list-cleaner/stripper.php"]Keyword Stripper[/URL] by SEOBook
[URL="http://tools.seobook.com/ppc-ad-wrapper/"]Keyword Wrapper[/URL] & [URL="http://tools.seobook.com/ppc-ad-wrapper/negative-wrap.php"]Negative Keyword Wrapper[/URL] by SEOBook

[B]Backlink Tools -[/B]
[URL="http://www.inspyder.com/products/BacklinkMonitor/Default.aspx"]Backlink Monitor[/URL] by Inspyder (Free Version)
[URL="http://www.webconfs.com/anchor-text-analysis.php"]Backlink Anchor Text Analyzer[/URL] by Webconfs
[URL="http://tools.seobook.com/general/link-suggest/"]Related Link Suggestion[/URL] by SEOBook
[URL="http://www.webmaster-toolkit.com/link-appeal.shtml"]Link Appeal[/URL] by Webmaster Toolkit
[URL="http://www.internetmarketingninjas.com/broken-links-tool/"]Broken Link Checker[/URL] by IMN
[URL="http://www.webconfs.com/reciprocal-link-checker.php"]Reciprocal Link Checker[/URL] by Webconfs
[URL="http://www.opensiteexplorer.org/"]Open Site Explorer[/URL] by Moz
[URL="http://www.linkdiagnosis.com/"]Link Diagnosis[/URL]
[URL="http://www.iwebtool.com/rank"]PR Checker[/URL] by iWebTools
[URL="http://www.bloggerlinkup.com/"]Blogger Linkup[/URL] by Cathy Stucker
[URL="http://myblogguest.com/"]My Blog Guest[/URL] by Ann Smarty

[B]OnPage Tools -[/B]
[URL="http://juicystudio.com/services/image.php"]Image Analyser[/URL] by Juicy Studio
[URL="http://www.seo-browser.com/"]SEO Browser[/URL] by Anduro Marketing & Ian McAerin
[URL="http://www.seorch.eu/"]SEOrch [/URL]by Matthias
[URL="http://www.xml-sitemaps.com/se-bot-simulator.html"]Search Engine Bot Simulator[/URL] by XML Sitemaps
[URL="http://www.iwebtool.com/html_optimizer"]HTML Optimizer[/URL] by SEO Chat
[URL="http://www.bing.com/toolbox/webmaster/"]Webmaster Tools[/URL] by Bing
[URL="http://tools.pingdom.com/fpt/"]Website Speed Test[/URL] by Pingdom
[URL="https://developers.google.com/speed/pagespeed/insights"]Page Speed Test[/URL] by Google
[URL="http://ubersniffer.com/"]UberSniffer[/URL], HTTP Header Checker by Alessandro Martin
[URL="http://www.xml-sitemaps.com/"]XML Sitemap Generator[/URL] by XML-Sitemaps
[URL="http://www.microsoft.com/web/seo/"]SEO Tool Kit[/URL] by Microsoft
[URL="http://www.link-assistant.com/website-auditor/"]Website Auditor[/URL] by Link Assistant
[URL="http://www.screamingfrog.co.uk/seo-spider/"]Spider [/URL]by Screaming Frog

[B]SERP Tools -[/B]
[URL="http://serp-checker.ezmlm.org/"]SERP Checker[/URL] by ezmlm
[URL="http://mozcast.com/"]MozCast [/URL]by Moz
[URL="http://www.google.com/webmasters/tools/richsnippets"]Rich Snippet Tool[/URL] by Google
[URL="http://www.link-assistant.com/rank-tracker/"]Rank Tracker[/URL] by Link Assistant
[URL="http://www.micrositemasters.com/We-Met-In-Person"]MicroSiteMasters[/URL] (30 day Free Trial)

[B]Social Media Marketing -[/B]
[URL="http://synnd.com/"]Syndd[/URL] (Free Version)
[URL="https://hootsuite.com/"]HootSuite[/URL]
[URL="http://twitterfeed.com/"]TwitterFeed[/URL] by Bitly
[URL="http://www.sharedcount.com/"]Shared Content[/URL] by Yahel Carmon