Developers usually have their own stash of resources from which they learn or use in their work. I have acquired good links to resources online and offline over the years that might benefit devs of all ages. I am going to be sharing them here and any passer-by can contribute to this just by forking this file to help others.
Links here are to sites that have full-fledged courses on different topics, frameworks and languages.
- CodeSchool - Interactive | Videos | Web | Freemium
 - CodeAcademy - Interactive | APIs | User Created Tutorials | Free
 - Microsoft Virtual Academy - Videos | Vendor-specific | Hands-on | Certificate | Free
 - Dash - Interactive | Web | Free
 - New Circle - Videos | Freemium
 - Pluralsight - Videos | Freemium
 - LearnStreet - Interactive | Videos | Web | Free
 - Coding For Good - Quiz | Videos | Web | Free
 - SkilledUp - Search Engine
 - SlideRule - Search Engine
 - Udemy - Videos | Freemium | Certificates
 - RubyMonk - Interactive | Free
 - LearnYouNode - Interactive | Offline | Free
 - TagTree - Interactive | Free
 - Learn Git Branching - Interactive | Free
 - Git-It - Interactive | Free | Offline
 - Platzi - Free | Online | Video | Live
 - freeCodeCamp - Free | Online | Video | Interactive
 - CodeAvengers - Free | Online | Interactive
 - Level-up Tutorials - Free | Online | Video
 - RegexOne - Free | Interactive | Online
 - SqlBolt - Free | Interactive | Online
 - Hacksplaining - Free | Interactive | Online
 - KataCoda - Free | Interactive | Online
 - Saylor Academy - Free | Online
 - Educative.io - Freemium | Online
 - Scala-Exercises - Free | Online | Interactive
 
Like these ones, there are more collections of useful dev links out there.
- SuperHeroJS - Learning JS inside and out
 - Bento - Resourceful links to all things web
 - HTML5 Rocks - HTML5 and Web Techs
 - AngularJS-Learning - Butt-load of learning material on AngularJS!
 - Resources - Resources to front-end learning and tooling
 - Coderbits - Links to several useful learning materials and tools
 - HTML5 Please - HTML5 and CSS3 support cross-browser, alternatives and fallbacks
 - Cheatography - Cheat sheets available for most programming needs
 - Javascript: The Right Way - Guide for best practices
 - Airbnb JavaScript Style Guide - Thousands of star gazers say that this style guide for JS is quite solid
 - Javascript Glossary - Concise Javascript guide
 - ProgrammingAlgorithms - Collection of Algorithms on multiple languages
 - PencilTree - Collection of videos on multiple technologies
 - Free ASP.NET Courses - Collection of free courses for ASP.NET
 
Loads of screencasts and videos on various topics.
- Thinkster - AngularJS Tutorial
 - EggHead - Digestible screencasts on JS libs and tools
 - LearnAllTheNodes - Nodejs screencasts
 - NodeTuts - Nodejs video tutorials
 - CommunityCasts - A community-driven free archive of educational, tech and creative screencasts
 
Old school style learning offline and online.
- Zapier - Who better to teach APIs then Zapier
 - JS Books - Links to almost all free JS books online and for offline reading
 
Articles and tutorials on many topics with code
- Scotch.io - Beautiful site and well-written tutorials on mainly web techs
 - SitePoint - Articles and tutorials written on various topics and some with code
 - Tech.PRO - Social network for techies demonstrating their knowledge through coding posts
 - OdeToCode - Mostly on ASP.NET and JS
 - Codrops - Mind blowing tutorials on unique and interactive UI elements and styling
 - TutsPlus - Tutorials on most web techs out there
 - Rosetta Code - Learn by solving tasks; Answers in multiple languages
 - BlackWasp - Huge array of C# articles, tips and tricks
 
- Coding Mystery - Exciting escape-room-inspired programming puzzles
 - CodinGame - Play turn based games using programming skills
 - CodeCombat - Multiplayer coding game
 - CodeChef - Community of programmers solving progamming problems
 - CodeHunt - Educational coding game with C#
 - Codewars - Solve katas to earn ranks
 - TestForGeeks - Questions for self-assessment
 - Codetoki - Collect badges by solving problems
 - TalentBuddy - Solve problems on multiple tracks
 - HackerRank - Coding challenges. Community. Awesome jobs
 - CoderByte - Solve algorithmic problems or program bots for games
 - Screeps - MMO for programmers
 - exercism.io - Practice. Communicate. Pay it Forward.
 - CodeFights - Improve coding skills while having fun
 - AdventOfCode - Solve small programming puzzles
 - EmpireOfCode - Play the future
 - CheckIO - Game for coders
 - LeetCode - Preparing for technical interviews
 - edabit - Learn to code with interactive challenges
 
- BuiltWith - Ever wonder what particular techs were used to build a web app or site? Well, find out!
 - attachables - Revamped TODOs for Visual Studio
 - Shapeshifter - Hands down the best clipboard manager for Windows
 - Gisto - Code Snippet management in the form of Gists
 - Plunker - Better than its competitors e.g. JSFiddle and JSBin
 - .NET Fiddle - Write, save, execute and share .NET code right from the browser
 - cmder - Portable console emulator for Windows
 - Docs - Simple tool to curate online resources for a particular topic
 - Zeal - Offline API documentation browser for most popular frameworks and libs
 - DevDocs - Offline and Online API documentation browser for most open-source frameworks and libs
 - CodeShare - Real-time code sharing and hacking
 - CodeBeautify - Whole lot of code formatting and conversion online
 - Postman - Best way possible to test API development
 - Octotree - Browser extension to see GitHub repos in a tree structure
 - Marxico - The missing Markdown editor for Evernote
 - Astral - Manage GitHub star repositories easily
 - Mocky - Mock API responses with multitude of options
 - SqlFiddle - Write, save, execute and share SQL right from the browser
 - CodingGround - Code in almost all popular languages
 - Indent Guides - Adds vertical lines at each indent level
 - jQAPI - What jQuery documentation should have been. Available as desktop and offline app.
 - JSApp.US - Make Node.js apps on-the-fly!
 - HyperDev - Developer playground for building full-stack web apps, fast
 - RunKit - Node playground in the browser
 - HTTPBin - Endpoints to test out with HTTP
 - RequestBin - Inspect HTTP requests sent to it
 - Scastie - An interactive playground for Scala