Stack Overflow
Q&A for professional and enthusiast programmers
Space Exploration
Q&A for spacecraft operators, scientists, engineers, and enthusiasts
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
Blender
Q&A for people who use Blender to create 3D graphics, animations, or games
Super User
Q&A for computer enthusiasts and power users
Server Fault
Q&A for system and network administrators
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Mathematics
Q&A for people studying math at any level and professionals in related fields
DevOps
Q&A for software engineers working on automated testing, continuous delivery, service integration and monitoring, and building SDLC infrastructure
Raspberry Pi
Q&A for users and developers of hardware and software for Raspberry Pi
Meta Stack Exchange
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
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
3D Printing
Q&A for 3D printing enthusiasts