Are a community questions with the lists of some useful stuff: one-liners, shell functions etc - would be useful and allowed on the Unix.SE site?
Here I will repeat the comment that I posted on your question, which I think you removed.
The point with these list questions, is that in general they will not fit in the Q&A format that SO demands. Suppose you get 20 nice shell functions, when asking for them, then which answer should you accept?
Sometimes, a question evolves into a community wiki with a lot of useful information, see for example the history of this question: How to do integer & float calculations, in bash or other languages/frameworks?
However, in general if you start a question in that way directly, nobody will really be interested in, because lists of useful stuff can be easily found online. In my opinion SO is meant in the first place to ask questions on problems that you actually face.
I'm not sure what you mean by "list" questions. From Bernhard's answer I can speculate a few things. If you mean "what are your 10 most useful 1 liners?" this is a bad question because it's completely arbitrary and aimless, I would close it as not a real question because you don't have a a real problem. However if you mean a question that is one that is simply able to have multiple correct answers, like my question "How can I move files up one directory", I knew there'd be multiple correct answers, but I had a very specific goal in mind, this kind of question is ok. If you mean something else entirely then you'll have to clarify.