Stock Images
PicJumbo
this site offers free stock images to be used on commercial and personal work – http://picjumbo.com/
Where can you use picjumbo photos
- Parts of Website or Mobile App (background, etc.)
- Image Placeholders in Articles or Websites
- Image Placeholders in Templates for Sell
- Part of Template for Sell (Attribution greatly appreciated by pic jumbo)
- All Personal & Commercial works
They can afford to do this by having a TONNN of advertising so be careful where you click 
Free Digital photos
http://www.freedigitalphotos.net/
Free digital photos offers quite a few free images from different photographers that just ask for attribution (which you should always do any way)
This site also funded through advertising and also linking to the larger stock image site who they will get a commission from if you buy an images from one of the other stock image sites
Other Design Related tools
Placeit: https://placeit.net/ ( fancy demos and embed screenshots)
Niice — the design search engine: http://www.niice.co/
Pixel Dropr: http://pixeldropr.com/
Sidebar.io: http://sidebar.io/
Designer News: https://news.layervault.com/
Hail Pixel: http://color.hailpixel.com/ (intuitive color picker)
Helvetica vs. Arial Quiz: http://www.ironicsans.com/helvarialquiz/
Responsive Design tools
Twitter Bootstrap — http://getbootstrap.com/2.3.2/ (also a framework)
ami.responsive — http://ami.responsivedesign.is/
Usersnap — https://usersnap.com (very handy for bug identification and notes)
Responsinator — http://responsinator.com
Unsemantic — http://unsemantic.com/
Brackets — http://brackets.io/
responsivepx — http://responsivepx.com/
Project Managment
Trello — http://trello.com
Teamwork.com —https://www.teamwork.com/
Asana — http://asana.com
Basecamp — https://basecamp.com/
Activecollab –https://www.activecollab.com/
Issues/Bug Tracking
- Usersnap — https://usersnap.com/
- FogBugz — http://www.fogcreek.com/fogbugz/
- Pivotal Tracker — http://www.pivotaltracker.com/
- Redmine- http://www.redmine.org/
- Mantis — https://www.mantisbt.org
Communities
StackOverflow — http://stackoverflow.com/
CSS Weekly — http://css-weekly.com/
HTML5 Weekly — http://html5weekly.com/
Front-end Frontend — http://frontendfront.com
GitHub — http://github.com/
JavaScript Weekly — http://javascriptweekly.com/
Front-end Development tools
- Less css —http://lesscss.org/
- SaSS css — http://sass-lang.com/
- Twitter Bootstrap — http://getbootstrap.com/2.3.2/
- Twitter Bower — http://bower.io/
- HTML5 boilerplate — http://html5boilerplate.com/
- ReactJS — http://facebook.github.io/react/
- AngularJS — http://angularjs.org/
- JQueryUI — http://jqueryui.com/
- JQuery — http://jquery.com/
- Backbonejs — http://backbonejs.org/
- CanJS — http://canjs.com/
- YUI library — http://yuilibrary.com/
- NinjaUI — http://ninjaui.com/
- Grunt — https://github.com/cowboy/grunt
- ComponentJS — http://component.io/
- TodoMVC — http://todomvc.com/
- SpaceBase — http://spacebase.space150.com/
- xchema xtyle — http://xtyle.xchema.com
- Yeoman — http://yeoman.io/
Other stuff
Puppet (automation) — http://puppetlabs.com/
src: https://medium.com/web-development-resources/ ( worth a look this site is)