We have an absolutely ridonculous amount of tags, although not unexpected.
There are some single-use tags that should either be removed, merged, or synonymised. Add your personal pet peeves to the list, following the template, and update when/if an action is undertaken. Comment on the question as necessary.
Suggestion: I think cultural-tourism would be very ironic after the recent debate about the culture tag. Why not then just merge them all into the existing tag and declare it a bit broader and no longer controversial?
Suggestion: Now this did at one point get merged with gear but apparently it was one of the reversed pair of synonyms. It did look like it got put back the right way around according to the meta post, but apparently not since the tags are now separate. Anyway if gear is a good tag, then clearly it should be the main tag. It is defined as: Equipment, devices, and more—if you pack it, it's travel gear. So you can see it was already specifically designed to cover electronic devices et al.
Suggestion: It's purpose is to cover questions covering multiple countries and is best used for questions asking for help deciding between which country to visit. But in this use we also have the more general destinations tag. So why not just make countries a synonym that redirects to destinations and declare it to be used only for this?
Suggestion: They're not really the same. Adventure is something unusual and probably lengthy like driving around Ireland with a fridge or crossing the steppe on horseback. Extreme is about putting yourself in danger like maybe diving off a cliff in Acapulco or travelling to a know war zone.