Stack Overflow
Q&A for professional and enthusiast programmers
Worldbuilding
Q&A for writers/artists using science, geography and culture to construct imaginary worlds and settings
Arduino
Q&A for developers of open-source hardware and software that is compatible with Arduino
Science Fiction & Fantasy
Q&A for science fiction and fantasy enthusiasts
Electrical Engineering
Q&A for electronics and electrical engineering professionals, students, and enthusiasts
Home Improvement
Q&A for contractors and serious DIYers
Woodworking
Q&A for professional and amateur woodworkers
Engineering
Q&A for professionals and students of engineering
Medical Sciences
Q&A for professionals in medical and allied health fields, students of those professions, related academics, and others with a sound understanding of medicine and healthcare-related sciences
Raspberry Pi
Q&A for users and developers of hardware and software for Raspberry Pi
Arqade
Q&A for passionate videogamers on all platforms
Physics
Q&A for active researchers, academics and students of physics
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Law
Q&A for legal professionals, students, and others with experience or interest in law