The tag reincarnated-as-a-slime for the series "That Time I Got Reincarnated as a Slime" currently has no synonyms. I suggest we add the following synonyms (refer to the current policy on tagging and synonymization):
The current tag name has 23 characters, possibly due to the former limit of 25 characters for tag names. Since we can now use up to 35 characters in a tag name, we could have that-time-i-reincarnated-as-a-slime as a synonym.
In fact, if this suggestion is acceptable, it might even be good for the longer name to replace the current one (rather than one being a synonym of the other) since the shorter name is a substring of the longer one.
Alternatively (or additionally), we could have the tag that-time-i-got-reincarnated-slime as a synonym, by taking all the words that are capitalized in the series name. Of course, there is some ambiguity in this, but I am using Wikipedia as a reference here.
The Japanese title of the series is "Tensei Shitara Slime Datta Ken", so we could have the tag tensei-shitara-slime-datta-ken as a synonym.
The series is also abbreviated as "TenSura", so we could have the tag tensura as a synonym.
Lastly, I think the tag tensura ought to be the primary tag, with the rest as synonyms, based on what the tagging policy says regarding series names that are too long to fit within the character limit but which also have a widely accepted abbreviation (namely, use the abbreviation as the primary tag).