A number of overworld sprites in Ruby and Sapphire appear to be directly based on Trainer class designs from Gold and Silver.
Has the GS hairstyle and hairband. This was later altered in Emerald:
Has the GS hairstyle.
Has the GS hairstyle, albeit green, as well as the outfit and earrings.
This sprite, while not used for any Trainers, appears to be based on the Firebreather's overworld sprite from Gold and Silver.
Has the GS hat, as well as a beard.
Has the GS hairstyle. Note the symmetrical bangs and longer pigtails.
This sprite, used for three different classes, appears to be based on the Super Nerd from Gold and Silver. The Collector sprite is the closest in appearance.
This sprite, used for the female Expert, appears to be based on the Medium from Gold and Silver, as seen by the hairstyle.
Has what appears to resemble the GS outfit. Note the shoes and clear distinction between shirt and shorts.
Has the GS bow.
This sprite is left unused in Ruby and Sapphire, providing further evidence to the overworld sprites being designed after the Gold and Silver Trainer classes.