Mathematics
Q&A for people studying math at any level and professionals in related fields
MathOverflow
Q&A for professional mathematicians
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
Electrical Engineering
Q&A for electronics and electrical engineering professionals, students, and enthusiasts
Role-playing Games
Q&A for gamemasters and players of tabletop, paper-and-pencil role-playing games
Artificial Intelligence
Q&A for people interested in conceptual questions about life and challenges in a world where "cognitive" functions can be mimicked in purely digital environment
Academia
Q&A for academics and those enrolled in higher education
Puzzling
Q&A for those who create, solve, and study puzzles
Astronomy
Q&A for astronomers and astrophysicists
Physics
Q&A for active researchers, academics and students of physics
Linguistics
Q&A for professional linguists and others with an interest in linguistic research and theory
Mathematics Educators
Q&A for those involved in the field of teaching mathematics
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
English Language & Usage
Q&A for linguists, etymologists, and serious English language enthusiasts
Computer Science
Q&A for students, researchers and practitioners of computer science
Stack Overflow
Q&A for professional and enthusiast programmers
Biology
Q&A for biology researchers, academics, and students
Psychology & Neuroscience
Q&A for practitioners, researchers, and students in cognitive science, psychology, neuroscience, and psychiatry
History of Science and Mathematics
Q&A for people interested in the history and origins of science and mathematics