Favorite 'retro' anime and manga?

Retro anime and manga are generally classified by a combination of age (roughly 20–30+ years old, typically 1990s or earlier), the use of hand-drawn cel animation, and distinctive artistic styles prevalent between the 1970s and early 1990s. Key markers include a 4:3 aspect ratio, thicker character line art, and a specific "vintage" aesthetic that evokes nostalgia.

Share some of your favorite classic anime and manga.