Raspberry Pi
Q&A for users and developers of hardware and software for Raspberry Pi
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
Stack Overflow
Q&A for professional and enthusiast programmers
Mathematics
Q&A for people studying math at any level and professionals in related fields
Aviation
Q&A for aircraft pilots, mechanics, and enthusiasts
Arduino
Q&A for developers of open-source hardware and software that is compatible with Arduino
Robotics
Q&A for professional robotic engineers, hobbyists, researchers and students
Database Administrators
Q&A for database professionals who wish to improve their database skills and learn from others in the community
Physics
Q&A for active researchers, academics and students of physics
Engineering
Q&A for professionals and students of engineering
Cryptography
Q&A for software developers, mathematicians and others interested in cryptography
Meta Stack Exchange
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Android Enthusiasts
Q&A for enthusiasts and power users of the Android operating system
Ask Ubuntu
Q&A for Ubuntu users and developers
Computer Science
Q&A for students, researchers and practitioners of computer science