You can get localaise Q n A for your team-specific needs. Easy to implement and integrate. Didn't even need to contact customer support and used it quite frequently for a quarter.
SO is a useful knowledge base for us, in a format that is familiar to anybody who ever needed to centre an element on a web page. I like that it gives pretty decent search results, and more often than not people will find what they need without having to ask on Slack. When writing a new question, it will offer you search results for similar articles, often saving you from duplicating something that has already been answered.