SEO Tools

1. Plagiarism Checker
 If you want to check duplicate content then you can use this tool.
http://smallseotools.com/plagiarism-checker/

2. Domain Tool
This tool will help to provide information about domain like domain created and expiry date, IP Location and many more.
http://whois.domaintools.com/

3. Link Checker
For HTML and CSS Validation checker you can use this tool.
https://validator.w3.org/checklink

4. Broken Link Checker
Online check website broken link(s)
http://www.brokenlinkcheck.com/

5. Web Page Speed Checker
Check website and mobile page speed.
https://developers.google.com/speed/pagespeed/insights/

6. Duplicate Content Checker
This tool find the duplicate content of the website
http://www.copyscape.com/

7. Responsive Site Checker
Check whether your website is responsive or mobile friendly
https://www.google.com/webmasters/tools/mobile-friendly/

8. Domain Age
If you want to find the domain age then this tool will help you
http://www.webconfs.com

9. Backlink Checker
Check the number of backlinks of any website
http://smallseotools.com/backlink-checker/

10. Keyword Density Checker
For any website you can easily check keyword density
http://smallseotools.com/keyword-density-checker/