Researchers could not find other lengths although they hypothesized that if someone wanted they could create a “mega” category. “It’s possible,” they concluded.
Funnily, book and story lengths actually do bunch up for commercial reasons. I read of one author whose kids book was semi accepted, but they needed another 80 pages to hit the next price point. (Basically, the unusually thin book would not "communicate value" on the shelf). Extending the story ruined the flow, so he decided to self publish online.
The same is true for film - opportunities to tell a 10 minute or 70 minute story are pretty rare, and I think techniques of film have just developed around that limitation. A 70 minute film might just leave viewers feeling confused.
It's interesting how in filmed stories there are the 2 main types - movie and tv series, where the shorter movie seems the more serious/central/important/prestigious etc form, the opposite of the situation with short story/novella vs novel. That's just from the historical accident of people seeing movies in cinemas, and series on TV, I guess.
70min movies can work fine - the 68 min Detour (1945), one of the first noirs, doesn't seem too short at all. Rick and Morty at 22 or so minutes does more than most 1 hour tv shows - an hour at that pace might be too much. Also, it seems that in the first decades or 50 years of cinema, plenty of 10 and 70 minute stories were shown, but recently you get the 'main feature' and nothing else.
Researchers could not find other lengths although they hypothesized that if someone wanted they could create a “mega” category. “It’s possible,” they concluded.