FREE SEO Tools

https://sitechecker.pro/ (get free website seo score online)
https://neilpatel.com/seo-analyzer/ (SEO Analyzer)
http://www.copyscape.com/ (Plagiarism Checker)
http://www.woorank.com/  (For website Analysis)
http://seositecheckup.com/ (For website Analysis)
http://www.sitemapdoc.com/ (Create rss.xml)
http://www.xml-sitemaps.com/(Create sitemap.xml)
https://www.google.com/webmasters/tools/mobile-friendly/ (Mobile-Friendly Test of Website)
https://developers.google.com/speed/pagespeed/insights/      (Page Speed Checker)
https://www.google.com/webmasters/tools/removals  (Remove outdated content - Enter the exact URL that you want removed from search results)
http://www.webconfs.com/
http://smallseotools.com/domain-authority-checker/ (Domain Authority Checker)
http://www.alexa.com/    (Alexa Rank Checker)
http://smallseotools.com/plagiarism-checker/ (Plagiarism Checker)
http://smallseotools.com/article-rewriter/ (Article Rewriter)
http://caseconvert.com/ (Uppercase to lowercase, count words, count characters, find and replace)
http://caseconverter.com/ (converts any text to either lower case, upper case, proper or sentence case)
http://word2cleanhtml.com/ (ConvertWord documents to Clean HTML)
http://convertonlinefree.com/  (Document to PDF Converter)
http://www.google.com/webmasters/tools/richsnippets (Google Snippet Preview)
http://www.siteliner.com/ (For internal duplicate content )
http://www.feedthebot.com/tools/alt/ (image SEO tool)
http://www.snippetoptimizer.net/ (Google Snippet Builder and Optimizer)
http://whois.domaintools.com/ (Lookup Domain and IP Ownership Records)
http://www.weburlopener.com/ (Opening multiple URLs in one click)
http://imgur.com/ (Free Image URL Hosting & Generate a public image URL )
http://www166.lunapic.com/editor/ (Online Image Editor, Resize, Crop for Twitter, Facebook, LinkedIn Covers)
http://www.photojoiner.net/ (Add Two or Three Photos in Single)
https://tinypng.com (PNG and JPEG compression)
http://www.brokenlinkcheck.com/ (Find Broken Link)
http://smallseotools.com/websites-broken-link-checker/ (Find Broken Link)
http://w3techs.com/sites (Find which technologies a particular website is using)
http://builtwith.com/    (Find which technologies a particular website is using)
https://goo.gl/ (Google URL Shortener)
http://www.aleydasolis.com/en/international-seo-tools/hreflang-tags-generator/ (hreflang Tags-Generator)
https://answerthepublic.com/(Find Long Tail Keywords)

https://www.keyword.io/ (Find Keywords)

Lightweight SEO tool which shows dynamics for the search results within the search page:

1. SERPTrends SEO Extension for Chrome 
2. 
   

Websites for Daily Search Engine Industry News & Updates:

1. http://searchengineland.com/
2. http://searchenginewatch.com/
3. https://www.seroundtable.com/
4. http://www.searchenginejournal.com/