I have seen created tags that may/may not be useful as Sports SE progresses.
Several examples are: field-goal, down, and zinedine-zidane. field-goal and down was in regards to in-game scoring/characteristics of American football. zinedine-zidane plays football (soccer).
Most existing tags cover sports (american-football, football, cricket), aspects (rules, equipment), how-tos (technique, scoring), and statistics to name a few.
How far within a particular sport/event/etc do we want to create tags for? What is a good basic guideline to follow when considering tag creation?
From the help center: "As a general rule, you should avoid creating new tags if possible, and new users are not allowed to create new tags. Even if you have sufficient reputation, you should only create new tags when you feel you can make a strong case that your question covers a new topic that nobody else has asked about before on this site."
The purpose of this question is to reasonably scope useful tags...not place stringent requirements on what merits creation of a tag. For example, zinedine-zidane or any athlete-specific tag would not be considered reasonably scoped or useful. Adding a tag based on mention or reference would not be considered reasonably scoped or useful unless the question is about said tag (see this).
Q: The big-list tag has been introduced. Does a tag with the verbiage "Please do not ask too many of these." merit tag creation in the first place?
A: Such a tag (and other similar tags) do not describe the content of the question.