Stack Overflow
Q&A for professional and enthusiast programmers
Super User
Q&A for computer enthusiasts and power users
Software Engineering
Q&A for professionals, academics, and students working within the systems development life cycle
Meta Stack Exchange
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Worldbuilding
Q&A for writers/artists using science, geography and culture to construct imaginary worlds and settings
Code Golf
Q&A for programming puzzle enthusiasts and code golfers
Code Review
Q&A for peer programmer code reviews
History
Q&A for historians and history buffs
Personal Finance & Money
Q&A for people who want to be financially literate
Information Security
Q&A for information security professionals
Bitcoin
Q&A for Bitcoin users, developers, and enthusiasts
Politics
Q&A for people interested in governments, policies, and political processes
Biology
Q&A for biology researchers, academics, and students
Retrocomputing
Q&A for vintage-computer hobbyists interested in restoring, preserving, and using the classic computer and gaming systems of yesteryear
Philosophy
Q&A for those interested in the study of the fundamental nature of knowledge, reality, and existence
The Workplace
Q&A for members of the workforce navigating the professional setting
Mathematics Educators
Q&A for those involved in the field of teaching mathematics
User Experience
Q&A for user experience researchers and experts
History of Science and Mathematics
Q&A for people interested in the history and origins of science and mathematics
Mathematics
Q&A for people studying math at any level and professionals in related fields
Puzzling
Q&A for those who create, solve, and study puzzles
Science Fiction & Fantasy
Q&A for science fiction and fantasy enthusiasts
Interpersonal Skills
Q&A for people looking to improve their interpersonal communication skills
Area 51
Q&A for proposing new sites in the Stack Exchange network