There are numerous questions in both hide and show. The majority of these questions are directly related to jQuery animations while a decent amount of others are in regards to hiding various $x. The jQuery related questions would probably be better suited retagging hide/show to animation or even jquery-animation as the more general "hook" and specify that you are hiding/showing something with your animation. The questions not related to animation effects should probably just have these tags removed altogether as they provide no helpful information.
In addition there's also show-hide, showhide, hideshow, auto-hide, autohide. Some of these like 'showhide/hideshow' and 'autohide/auto-hide' have just a few tags and I'll probably get rid of those today. However, show-hide has nearly 400 questions associated with it; it may be better to get rid of those tags en masse.
The only tags left from these are hide, show and show-hide which represent about 1600~ questions. With that many questions is there some mass action that can be taken to merge those tags with animation or otherwise get rid of them?