Tools to check SEO issues?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

• 
  Pankaj Asopa: Hello Everyone,
  
  Excited with this community, just a beginner in SEO, following basic rules for SEO to maintain websites on Google.
  
  Do we have any tools to check SEO issues? as GWT gives us the options to check issues but is there anything else which goes more broader? ;
• 
  Richard Hearne: Tools I use:
  
  * Botify.com - diagnostic
  * DeepCrawl.com - diagnostic
  * ScreamingFrog.co.uk - diagnostic
  * Majestic.com - link data
  * SEMrush.com - competitive research
  
  The first 2 above are great for diagnostic evaluation, but bear in mind that virtually all of the above are paid tools.
• 
  Pankaj Asopa: I see, though thanks for the suggesting them, is there any free one?
• 
  Richard Hearne: ScreamingFrog has a free version which allows you to crawl up to 500 URLs (I think 500).  ;That may be enough for small sites once you exclude images/js/css etc. from your crawl.  ;You can also use tools like XENU to find broken/redirected links.  ;It's free.
• 
  Pankaj Asopa: Thanks
• 
  Chris Haigh: I'd also sign up to Google analytics - no it doesn't necessarily show SEO issues, but it can highlight places for improvement, e.g. pages with high bounce rates and where your audience is coming from - social media / referalls / organic - so you have more of an understanding of your site and how it can be improved.
• 
  Pankaj Asopa: Thanks, I already added GA, I will check the improving areas again.
• 
  Chris Haigh: And make sure your sites Mobile-friendly, as im sure you're aware of the April 21st Google update :)
• 
  Pankaj Asopa: Yes, I am having eyes on GWT and trying to resolve all the pointed issues :-) 
• 
  Farhan Fawzer: Awesome