Tools

GitHub Student Pack
A free resource pack from GitHub.
ngrok
A reverse tunnel. Run a server locally in any language and give it a public domain. Great for testing and demoing.
BrowserSync
Time synced browser testing. Useful when sharing a design to teammates and on multiple devices. Usually used with gulp or grunt.
Alexa Skills Kit
Voice enable any app or service with Amazon Alexa.
F.lux
Save your eyes from blue light eye strain.
Origami (mac)
A free tool from Facebook for designing modern interfaces and interactions.
Vagrant
Create and configure reproducible, portable, lightweight development environments.
Studio 3T
A GUI to make navigating MongoDB quicker and easier.

Code

Code Pen
An HTML/CSS/JavaScript code editor in your browser with instant previews and tons of snippets and inspiration.
Cody House
A free library of HTLML, CSS, and JS nuggets with tutorials.
Hover
A CSS3 Animation hover effects library.
Start Bootstrap
Free Bootstrap starter templated for different types of sites.
Boot Snipp
Free Bootstrap code snippets for design elements.

Design

Graphic Burger
An array of design resources such as mockups, UI kits, icons, backgrounds, etc.
100 Days of Fonts
A great place to find beautiful combinations and usages of Google Fonts and color schemes.
Pttrns
Same as Pattern Tap, but for mobile design patterns. (iOS and Android)
UX Archive
Can't figure out the best user flow for your mobile hack? UX Archive lists just about every flow or user task from the best apps.
Stock Photos That Don't Suck
An ongoing list of the best stock photo sites.
User Inter Faces
A database of profile pictures for mockups and demos.

Icons

Font Awesome
Font and CSS toolkit with 675 icons to use in your designs.
The Noun Project
Thousands of amazing, detailed icons useful for your hacks.
Icon Monstr
Icon sets for just about anything.