In Tag management 2019 it was suggested to use the tag grad-curl-div as an umbrella tag for questions concerning gradient, curl, and divergence. (Currently, gradient is a synonym of vector-analysis, while curl and divergence-operator exist as separate tag. So the situation for these three notions is not exactly symmetric.) This suggestion was also discussed a bit in chat, namely in November 2019 and in December 2019.
In the previous post you can find also proposal for the tag-info for this tag. The linked post in the tag management thread has currently score 8.
This would be a compromise solution between users who want gradient as a separate tag and the users who would consider this as having too many narrow tags. (Which is sometimes a problem, considering that there are only five slots for tags on a question.)