I find this plot structure tired and boring so I'm always on the lookout for movies that don't follow it. They are hard to find! (Also, I probably don't have an excellent memory to recall them later when I do find them.)

Horror movies in general seem to have more freedom to play with plot structure than other genres. Every film, regardless of plot, needs to have something that makes the audience want to watch to the end of the film. With horror, it's often putting the question in the audience's mind "what is happening?" That can be compelling enough to propel the viewer to the end so the film often doesn't need to have a protagonist go through some emotional journey.

It's been a while since I've seen them, but I don't think The Ring or The Grudge follow this plot form. It's probably telling that both of those are adaptations of non-Western films. I don't think Alien follows this structure either: Ridley is basically right all along and just has to survive.

I think Goon is an underrated comedy, and it doesn't really fit the three-act structure well. It certainly has conflict and climax, but Doug doesn't really go through any internal crisis. Instead, he's more often the catalyst for internal change in other characters.

Some that I've watched that I think qualifies, depending on how loosely you want to interpret it. Been a while since I watched most of these, so won't fight anyone if they disagree. Also didn't consider comedies or war, horror and very low budget movies as there are so many that fit from those categories.

Dawn Breaks Behind the Eyes - https://www.imdb.com/title/tt8518302/

Good One - https://www.imdb.com/title/tt30319516/

Hard to Be a God - https://www.imdb.com/title/tt2328813/

Rosencrantz & Guildenstern Are Dead - https://www.imdb.com/title/tt0100519/

The Wanting Mare - https://www.imdb.com/title/tt2267554/

In a Savage Land - https://www.imdb.com/title/tt0151047/

Welcome the Stranger - https://www.imdb.com/title/tt5716280/

Tinker Tailor Soldier Spy - https://www.imdb.com/title/tt1340800/

The Hourglass Sanatorium - https://www.imdb.com/title/tt0070628/

Where do we draw the line?

Does an anthology approach like Playtime (1967, dir. Jacques Tati) count? It's got kind of an arc to it, but doesn't really have anything like a recognizable struggle with an antagonist. Unless you view brutalism as the antagonist, I guess.

8½ (1963, dir. Federico Fellini) could, likewise, be shoehorned into a discussion of the arc of the film--which it, itself deconstructs in the third scene or so. It's primarily a film about making the film. There's _kind of_ a journey the protagonist goes on, but does it really count as being this same plot?

In biology one thing is made similar to other ("assimilated") in order to absorb it. In the same way, some ideas are packed in some format known to be easy to digest.

The trick in this topic is how dissimilar to some vague canon should a story be to qualify for an answer to your question.

Would you say Alien is a good example?

> meet someone who shows them a different way of being

Enter the Manic Pixie Dream Girl.

Twelve Angry Men

Primer

Holy Motors

Le Voyage dans la Lune

Irréversible

Before Sunrise / Before Sunset

Not a movie but most motorsports do not follow the monomyth. The cars or trucks or tractors compete, but none of them are designated protagonist. The progression is usually from slower and cheaper vehicles to more expensive and faster ones, to build excitement for the audience.

The adventure of the individual vehicle is that it prepares for the races, it practices, it tunes, then it competes, and then it either wins or loses. And then, budget permitting, it prepares for the next race.