Asklemmy

I know this isn't what you want to hear, so just tell me to shut up if you want. But, this feels a little performative. You must know and like movies in all of those catagories. Why not pick your favorites and go with those? I expect you'll enjoy the end result more than 'classics' with no specific meaning to you.

Akira (1988) for 2D animation.

Though now that I'm re-reading your post body, it seems that the actual poster doesn't really matter?

If I had to select a few for the genres (without looking at their posters and just purely from what I think are iconic films for each genre), then:

• Indiana Jones for Action/Adventure (to be fair, very iconic posters)
• Monty Python for Comedy
• Shawshank Redemption (or Citizen Kane if you prefer older classics) for Drama
• Toy Story for 3D animation
• Akira (or Spirited Away, but if you prefer Western then Lion King is another good classic) for 2D animation
• 2001: A Space Odyssey (or Star Wars if that's more of your thing, very iconic posters) for Sci-Fi
• The Silence of the Lambs for Thriller (very iconic poster too)
• The Lord of the Rings trilogy for Fantasy

They're mostly American/Hollywood films but that's what most people would identify as iconic. There are a lot of other iconic films from other regions too such as French, Italian, Soviet, and Japanese films that I think may not be as iconic depending on your region but they're just as good and maybe even better. 400 Blows (French) is a pretty iconic Drama film for example.

I think one of them has to be North By Northwest, the Alfred Hitchcock thriller.

Fantasy

The Lord of the Rings for sure

For decoration a basement, these would do:

• Action/Adventure: Raiders of the Lost Ark
• Comedy: Airplane!
• Drama: The Seven Samurai
• 3D Animation: The Incredibles
• 2D Animation: The Iron Giant
• Science Fiction: Blade Runner
• Mystery/Thriller: The Third Man
• Fantasy: The Princess Bride

Limiting it to one film per category is tricky, especially since some of them are so broad, and "animation" isn't even a genre but a medium. I'm going to try to choose films that represent a turning point in their respective category, after which films of that type were forever changed in some way. These may be the "iconic/obvious" options, but they're also films that just about any movie lover ought to be proud to honor on their wall.

• Action/Adventure: Raiders of the Lost Ark
• Comedy: Spinal Tap
• Drama: Citizen Kane
• CGI/3D Animation: Toy Story
• 2D Animation: Spirited Away
• Science Fiction: 2001: A Space Odyssey
• Mystery/Thriller: Rear Window
• Fantasy: The Fellowship of the Ring

I’m choosing to ignore the idea of sticking to categories as I think it makes it more limiting than it needs to be, and because some of the best films cross or defy genres.

I’m also going to say in passing that these questions inevitably get dominated by recent films. Whenever someone asks for a list of the greatest movies or albums of all time, we tend to respond with the ones we remember from our teenage years. It’s interesting as a social question, but there’s a definite recency bias that’s driven both by our memories and by the fact that tastes change.

With that all said, I think that the Jaws poster is probably one of the best I’ve ever seen. It is simple and immediate. There is no way to see it and not get the point of the movie.

Pulp Fiction and The Graduate were both great with their dirty book cover style aesthetic. Sort of similarly, Star Wars reproduced a very iconic book cover/movie poster format but executed it brilliantly.

Full Metal Jacket with the “born to kill”/peace sign helmet is more toned down, but captures the film very well.

Fear and Loathing also had a brilliant poster - that one where it looks like an acid trip.

Visually, 2d animation posters cant be more iconic than AKIRA. And for sci fi, Jurassic Park really is on another level of iconic. You recognise the franchise style easily and it's been around for decades.

As for the other categories, I don't have such strong opinions but I'll try:

• Indiana Jones -The Mask
• Casablanca
• The Incredibles
• Akira
• Jurassic Park
• Vertigo
• The Never Ending Story

What I’m trying to do is select eight of the most iconic films of all time, across these genres:

Science Fiction

The only answer then is the original "Star Wars: A New Hope" poster