If you had to pick a single entry in all of pre-2000 anime (that you have seen yourself) that you'd say would be the best purely in terms of visuals, what would it be? While something like End of Evangelion or even Evangelion itself would be a common choice for its fluid animation and immersive surreality, I was personally very impressed by how both Patlabor films looked. The shots of the city were amazing to look at but I also really liked the realistic character designs and facial expressions. Akira would also be a good choice for the amount of work that went into its animation and for not having aged a bit in terms of how it looks, as opposed to most anime from the 80s.
I think the visual aspect of these works is what really stands out to me when it comes to retro anime as opposed to modern-day entries in the medium. In this decade, 2D animation has become more and more scarce and lots of studios are replacing it with CG for certain aspects of the animation like mecha sequences or anything with cars in it.
I guess this could also be a general sakuga (in retro anime) appreciation thread.