I did some search. Came up with nothing relevant. Is there a way to tag movies, say I have 100 Criterion Collection movies, is there a way to create Criterion tag and apply it to the movies by hand? I found a Wiki page, but it may be outdated, at least my (default 18.2) interface does not have such menu items.
Edit: Found it ...
I found a way to tag movies - kind of creating a list, but unfortunately in main listing it does not show tags. That is, when in movie listing then I cannot see my Criterion movies tagged. Will check that add-on now, thanks.
Ok, you want the tag visible when you browse your library, not just to use them to create a playlist. The add-on won't do it. It will just make it easier to add to the existing tags.
You will need to put on your skinners hat and modify the views.
Which skin are you using?
Do you have only one tag per movie or multiple?
If multiple, how do you want to handle them? View all tags when browsing or view only "Criterion"?
I do not foresee using multiple tags per movie. But you never know, it may become handy, in that case I'd like to see them all. My Kodi is 18.2 and skin is Estuary.