Are there any crowdsourced knowledge bases that focus on common questions in technical topics?

Yes — there are several crowdsourced knowledge bases and Q&A communities that focus on technical topics and common questions. A few of the best-known ones are:

• Stack Overflow — the biggest community for programming and software development questions.
• Server Fault — for sysadmin, networking, and infrastructure questions.
• Super User — for general tech questions about software and hardware.
• Ask Ubuntu / Unix & Linux — focused on Linux and Unix-related issues.
• Stack Exchange network — includes many topic-specific technical communities.
• Reddit communities like r/learnprogramming, r/sysadmin, r/networking, though these are less structured as knowledge bases.
• GitHub Discussions and project-specific wikis/issues — useful for questions about particular open-source tools.
• Wikipedia / Fandom / community wikis — not Q&A-first, but often crowdsourced repositories of technical knowledge.

If you mean a more structured “knowledge base” of common technical questions and answers, Stack Exchange sites are probably the closest fit.

If you want, I can also suggest:

1. the best one for a specific technical area, or
2. platforms that are more “knowledge base” than “forum/Q&A.”