Useful Referrals

For SEO Jargons

• MozJargon
• On-Site SEO
• International SEO
• Searchmetrics
• .htaccess Guide
• robots.txt File

For SEO Updates

• Search Engine Land
• Google Algorithm Change History

Useful Tools

• SEOChat Tools
• Broken Link Checker 
• Image Alt Attribute Checker
• Online Sitemap Generator
• Small SEO tools Cloaking Checker
• SEO Tools Cloaking Checker
• GZip Compression
• Chrome Developers Tools For more details on how to use it click here.
• Google SERP Snippet Optimization Tool: Identifies truncation issues with meta titles and descriptions. Also generates a live preview of how your web pages currently appear in Google search results. SEOMOFO is one such tool.
• Am I Responsive: Check responsiveness of your website
• KnowEm: Analyses your web page to see if it’s well-optimized for social sharing. It checks for markup from Facebook, Google+, Twitter, and LinkedIn.

Useful Tools for Keyword Suggestions

• Answer the Public: Good for Keyword Suggestions/Questions/Prepositions/Comparisons/Alphabetical
• UberSuggest: Good for Keyword Suggestions
• Keyword.io: Good for Youtube Keyword Suggestions
• SEOChat Google Keyword Suggestions: Good for Keyword Suggestions
• Soovle: Scrapes Google, Bing, Yahoo, Wikipedia, Amazon, YouTube, and Answers.com to generate hundreds of keyword ideas from a seed keyword. Very powerful tool, although the UI could do with some work.
• Google Keyword Planner / Trends / Webmaster Tools / Analytics / Sheets — Must-use tools for all SEOs. Find and research keywords (Keyword Planner) and identify trends (Trends). Identify and fix website issues (Webmaster Tools). Analyse how many people are visiting your website, who they are, and where they come from (Analytics). Gather, process, and analyze all kinds of SEO-related data (Sheets).
• Bing Webmaster Tools
• LSIgraph.com: Latent Semantic Indexing (LSI) keywords generator. TextOptimizer is another very similar tool that does roughly the same job.
• KWFinder: Long tail keyword research tool.
• Moz’s Keyword Explorer: Keyword Explorer offers Volume and Difficulty, Opportunity: Relative CTR of the organic results on a SERP, Importance: How critical the keyword is to your campaign, Potential: A combination of all keyword metrics to help you prioritize

For Designing

• Adobe Kuler

Blogs

• Moz Blog
• HemmingwayApp: Improves the clarity of your writing by highlighting difficult to read sentences, “weak” words, and so forth. A must-have paid tool for bloggers. 
• Small SEO Tools Plagiarism Checker