There are a number of tools available to assist with SEO. Some are made available by search engines, and some are developed by agencies and individuals who specialise in SEO. Most are available for free.
Google Search Console
Google provides guidelines to webmasters and tools to help ensure your website is being indexed.
Open Site Explorer
Moz provides a useful tool called Open Site Explorer, which can help you determine the value of links from particular sites.
Tools from SEOBook
SEObook provides a number of tools that assist any SEO. For example, Rank Checker is a Firefox extension that allows you to save a number of keywords and to perform regular searches on them, giving you the ranking of your chosen URL for each keyword in the search engines selected. They also have tools to help with keyword discovery.
Keyword discovery tools
There are a number of tools available, some free and some paid for, to assist with keyword discovery. Some include:
Google AdWords Keyword Planner
Trellian’s KeywordDiscovery tool
Bing Ads Intelligence
SEO PowerSuite Rank Tracker (the trial version has limited functionality)
Webmaster World (www.webmasterworld.com) is frequented by SEOs and webmasters aiming to stay current with latest trends and search engine updates.
Google Merchant Center
The Google Merchant Center allows you to mark up any products you sell through eCommerce, ensuring that they also rank for relevant search results.
The Moz SEO toolbar (moz.com/products/pro/seo-toolbar) gives instant metrics while viewing SERPs or web pages.
Screaming Frog (www.screamingfrog.co.uk/seo-spider) allows you to crawl website URLs and analyse the onsite SEO.
AWR (www.awrcloud.com/login.php) gives you access to rankings for desktop, mobile, and local searches.