Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Super User
Q&A for computer enthusiasts and power users
Stack Overflow
Q&A for professional and enthusiast programmers
Raspberry Pi
Q&A for users and developers of hardware and software for Raspberry Pi
Vi and Vim
Q&A for people using the vi and Vim families of text editors
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
English Language & Usage
Q&A for linguists, etymologists, and serious English language enthusiasts
Science Fiction & Fantasy
Q&A for science fiction and fantasy enthusiasts
Android Enthusiasts
Q&A for enthusiasts and power users of the Android operating system
Bicycles
Q&A for people who build and repair bicycles, people who train cycling, or commute on bicycles
Server Fault
Q&A for system and network administrators
Physics
Q&A for active researchers, academics and students of physics
Worldbuilding
Q&A for writers/artists using science, geography and culture to construct imaginary worlds and settings
Arqade
Q&A for passionate videogamers on all platforms
Biology
Q&A for biology researchers, academics, and students
Ask Different
Q&A for power users of Apple hardware and software
Cross Validated
Q&A for people interested in statistics, machine learning, data analysis, data mining, and data visualization
Code Review
Q&A for peer programmer code reviews
Software Engineering
Q&A for professionals, academics, and students working within the systems development life cycle
Puzzling
Q&A for those who create, solve, and study puzzles
Motor Vehicle Maintenance & Repair
Q&A for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles
Board & Card Games
Q&A for people who like playing board games, designing board games or modifying the rules of existing board games
Politics
Q&A for people interested in governments, policies, and political processes
Photography
Q&A for professional, enthusiast and amateur photographers
Music: Practice & Theory
Q&A for musicians, students, and enthusiasts
Astronomy
Q&A for astronomers and astrophysicists
Web Applications
Q&A for power users of web applications
Academia
Q&A for academics and those enrolled in higher education
Code Golf
Q&A for programming puzzle enthusiasts and code golfers
Stack Apps
Q&A for apps, scripts, and development with the Stack Exchange API
Mathematics
Q&A for people studying math at any level and professionals in related fields
Information Security
Q&A for information security professionals
Personal Finance & Money
Q&A for people who want to be financially literate
Game Development
Q&A for professional and independent game developers
User Experience
Q&A for user experience researchers and experts
Graphic Design
Q&A for Graphic Design professionals, students, and enthusiasts
Electrical Engineering
Q&A for electronics and electrical engineering professionals, students, and enthusiasts
Meta Stack Exchange
Q&A for meta-discussion of the Stack Exchange family of Q&A websites