Stack Overflow
Q&A for professional and enthusiast programmers
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
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
English Language & Usage
Q&A for linguists, etymologists, and serious English language enthusiasts
Arqade
Q&A for passionate videogamers on all platforms
Photography
Q&A for professional, enthusiast and amateur photographers
Psychology & Neuroscience
Q&A for practitioners, researchers, and students in cognitive science, psychology, neuroscience, and psychiatry
Electrical Engineering
Q&A for electronics and electrical engineering professionals, students, and enthusiasts
Worldbuilding
Q&A for writers/artists using science, geography and culture to construct imaginary worlds and settings
Super User
Q&A for computer enthusiasts and power users
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
Islam
Q&A for Muslims, experts in Islam, and those interested in learning more about Islam
Academia
Q&A for academics and those enrolled in higher education
Biology
Q&A for biology researchers, academics, and students
Law
Q&A for legal professionals, students, and others with experience or interest in law
Space Exploration
Q&A for spacecraft operators, scientists, engineers, and enthusiasts
Project Management
Q&A for project managers
Video Production
Q&A for engineers, producers, editors and enthusiasts spanning the fields of video and media creation
Writing
Q&A for the craft of professional writing, including fiction, non-fiction, technical, scholarly, and commercial writing
Movies & TV
Q&A for movie and TV enthusiasts
Parenting
Q&A for parents, grandparents, nannies and others with a parenting role
Politics
Q&A for people interested in governments, policies, and political processes
Music: Practice & Theory
Q&A for musicians, students, and enthusiasts
Android Enthusiasts
Q&A for enthusiasts and power users of the Android operating system
Meta Stack Exchange
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Ask Ubuntu
Q&A for Ubuntu users and developers
Pets
Q&A for pet owners, caretakers, breeders, veterinarians, and trainers