Currently the tags maximal-ideals and prime-ideals exist (161 and 221 questions respectively).
These tags have been discussed in the past here and here. I am not sure whether a consensus was reached. (Perhaps in the first instance it seems that the voting and the comments that most users expressed the opinion that we do not need these tags. Maybe they changed their opinion before the issue was raised again. Maybe there were less votes on the second proposal because it was less focused.)
Anyway, I see two reasonable options: Either we keep these two tags or we make them synonyms of ideals. What do you think about this issue?
I am aware that there is a thread http://meta.math.stackexchange.com/questions/22348/tag-management-2016 where tag-related issues are usually discussed. But I think that it is better to post a separate question if it is likely that there will be longer discussion about the tags. Moreover, since this issue was raised in 2014 and 2015 thread, I did not like the idea to repost it in 2016 thread again.