I can't think of anything else that the teleportation tag would be used for, at least not within the scope of actual physics (and hence of this site). Unless there is some such thing, yes, I'd say go for it.
Of course there do seem to be some existing questions with the teleportation tag which quantum-teleportation would not apply to. Most of them are ...
For the time being for pragmatic reasons. Phys.SE used to have a quantum-computing and a quantum-computation tag, which were often misused by some users whenever they had to compute something in quantum mechanics. This practice stopped once they were redirected to the quantum-computer tag.
The weak-force tag and the weak-interactions tag were merged into the weak-interaction tag in 2014, partly spurred by this 2013 meta post.
General tip: Other synonym tags can be suggested on this meta page.
I) Specifically about covariance:
1) The covariance tag is supposed to cover whatever-notion-the-physical-system-in-the-question-is-covariant-under, typically relativistic covariance, but also more abstractly, e.g., contravariant and covariant tensors not necessarily in the context of relativity.
All other uses of the covariance tag than the above are ...
Contrary to merging of tags, the creation of synonyms does not alter posts retroactively. If a question is edited after the synonym was created, the tags of the question will conform with the new synonym rules.
In the future just raise such non-controversial merge requests1 in chat (as opposed to meta), and a moderator will take action.
Note that synonyms are reversible while merges are irreversible (=hard to unshuffle). This is why we often hesitate to perform merges.
1 I changed OP's original wording burninate request into merge request, ...
if the Phys.SE community thinks a frw-universe tag would be useful, and
if somebody would like to be custodian over the frw-universe tag, then it seems like a good idea to undo the synonym.
In an ideal world you are right: Let's tag all the questions as precise as possible. The problem is that we are only allowed to use 5 tags. And many users would ...
Representation theory is more general than group representations as it e.g. includes Lie algebra representations.
I have just made the group-representations tag a synonym of the representation-theory tag. (It was proposed in 2016 with currently 1 upvote.) Depending on feed-back from the community, we can later merge or undo the synonym.
The particle-physics tag (currently with approx. 3500 questions) is one of a few primary tags. Ideally all questions should be tagged with a primary tag.
The elementary-particles tag (currently with approx. 200 questions) is a secondary tag. It is mainly used for particle physics questions where it is important to distinguish between elementary particles and ...