Those resources which I couldn't think of a collective title!

Bitly - https://bitly.com/ Link Shortener

BlogTopicGenerator - http://www.hubspot.com/blog-topic-generator

Bubbl.Us - https://bubbl.us/ Mindmap Generator

Builtwith - http://builtwith.com/ Shows who built any website

Contact Form 7 - http://contactform7.com/

Copyscape - http://www.copyscape.com/ Check to see if your work was copied -useful if you are outsourcing

Dmoz - https://www.dmoz.org/ Niche Ideas

Dropbox - https://www.dropbox.com Storage

E.ggtimer.com - http://e.ggtimer.com/ So simple but so useful - Timer

Editorial Calendar WP - https://wordpress.org/plugins/editorial-calendar/

Free Headline Analyser - http://coschedule.com/headline-analyzer

Google Alerts - https://www.google.com/alerts

Google Drive - https://www.google.com/drive

Google pagespeed test - https://developers.google.com/speed/pagespeed/insi...

Google URL Shortener - https://goo.gl/

Grammarly - https://www.grammarly.com/

Hemingway - http://www.hemingwayapp.com/ Make your sentence shorter

Internet Crime Complaint Centre - http://www.ic3.gov/default.aspx Who knows when this could come in handy!

LastPass - https://lastpass.com/ Probably the one resource I couldn't do without. Password generator

Mail Chimp - http://mailchimp.com/ Autoresponder

Overstream - http://www.overstream.net/ Text over videos

SimilarWeb - http://www.similarweb.com/ What is similar to your site.

Stat Counter - https://statcounter.com/

Trello - https://trello.com/ Organisation tool

Website Grader - https://website.grader.com/