Mathematics
Q&A for people studying math at any level and professionals in related fields
Mathematics Educators
Q&A for those involved in the field of teaching mathematics
Area 51
Q&A for proposing new sites in the Stack Exchange network
Cross Validated
Q&A for people interested in statistics, machine learning, data analysis, data mining, and data visualization
Meta Stack Exchange
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Psychology & Neuroscience
Q&A for practitioners, researchers, and students in cognitive science, psychology, neuroscience, and psychiatry
Physics
Q&A for active researchers, academics and students of physics
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
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
Signal Processing
Q&A for practitioners of the art and science of signal, image and video processing
Project Management
Q&A for project managers
Quantitative Finance
Q&A for finance professionals and academics
Space Exploration
Q&A for spacecraft operators, scientists, engineers, and enthusiasts
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Stack Overflow
Q&A for professional and enthusiast programmers
Quantum Computing
Q&A for engineers, scientists, programmers, and computing professionals interested in quantum computing
Data Science
Q&A for Data science professionals, Machine Learning specialists, and those interested in learning more about the field
Robotics
Q&A for professional robotic engineers, hobbyists, researchers and students
History of Science and Mathematics
Q&A for people interested in the history and origins of science and mathematics
Puzzling
Q&A for those who create, solve, and study puzzles
The Workplace
Q&A for members of the workforce navigating the professional setting
Language Learning
Q&A for students, teachers, polyglots, and anyone interested in the techniques of second-language acquisition
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
Mathematica
Q&A for users of Wolfram Mathematica
Biology
Q&A for biology researchers, academics, and students
German Language
Q&A for speakers of German wanting to discuss the finer points of the language and translation
Android Enthusiasts
Q&A for enthusiasts and power users of the Android operating system
Ask Different
Q&A for power users of Apple hardware and software
Home Improvement
Q&A for contractors and serious DIYers
Philosophy
Q&A for those interested in the study of the fundamental nature of knowledge, reality, and existence
Academia
Q&A for academics and those enrolled in higher education
English Language & Usage
Q&A for linguists, etymologists, and serious English language enthusiasts
Software Recommendations
Q&A for people seeking specific software recommendations
Super User
Q&A for computer enthusiasts and power users
Music: Practice & Theory
Q&A for musicians, students, and enthusiasts
Information Security
Q&A for information security professionals