Blender
Q&A for people who use Blender to create 3D graphics, animations, or games
Stack Overflow
Q&A for professional and enthusiast programmers
Ask Different
Q&A for power users of Apple hardware and software
Super User
Q&A for computer enthusiasts and power users
Robotics
Q&A for professional robotic engineers, hobbyists, researchers and students
Physics
Q&A for active researchers, academics and students of physics
Raspberry Pi
Q&A for users and developers of hardware and software for Raspberry Pi
Signal Processing
Q&A for practitioners of the art and science of signal, image and video processing
Music: Practice & Theory
Q&A for musicians, students, and enthusiasts
Web Applications
Q&A for power users of web applications
Graphic Design
Q&A for Graphic Design professionals, students, and enthusiasts
Cryptography
Q&A for software developers, mathematicians and others interested in cryptography
Mathematics
Q&A for people studying math at any level and professionals in related fields
Meta Stack Exchange
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Cross Validated
Q&A for people interested in statistics, machine learning, data analysis, data mining, and data visualization
Electrical Engineering
Q&A for electronics and electrical engineering professionals, students, and enthusiasts
Ask Ubuntu
Q&A for Ubuntu users and developers
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Arduino
Q&A for developers of open-source hardware and software that is compatible with Arduino
German Language
Q&A for speakers of German wanting to discuss the finer points of the language and translation
Information Security
Q&A for information security professionals
English Language & Usage
Q&A for linguists, etymologists, and serious English language enthusiasts