Looking at the tags, I see that transformation tag is the first tag without a tag wiki. Upon further investigation I see questions that are barely related. Some of them are geometry related, some are to do with linear algebra and others are even to do with integration. Is this tag really constructive?
I wrote a tag excerpt pointing out the ambiguity of the term, and suggesting alternatives. I think that as long as the tag is used together with another tag, it is not a problem: e.g., in the combination probability-distributions transformation the second tag adds some information.
I suggest editing the questions with no other tag: there are about 50 of those, and they appear at the beginning of this list. In some cases the tag can be replaced by others, in others it can be kept because addition of other tags clarifies the meaning. And many of those questions could use a better title too.