The Flasher - Middle age white male in a brown trench coat. Usually shown in a simulated photograph where he (never a she) is flashing (holding his coat open, back turned to photographer) an elderly woman.
The Gay Male - An older, well dressed (again) white male, must have a mustache. Depicted in morality films as getting his rocks off of checking out younger boys. It is also weird that gays were/are thought of as sexual deviants.
The lesbian - This is kinda sketchy territory. I've only seen one morality film, that depicted two teenage girls in some type of lesbian relationship (one unwittingly falling prey to the temptations of the evil lesbian seductress). However in psychology books, and sexuality books, they are depicted as women with short hair. Again playing on concept that homosexuals are deviants of some sort (only in the morality films).
The Dog Fucker - I've only seen this mentioned in one psychology book. It said that when shown a picture of a man engaging in sexual acts with a dog, the average person displayed an expression of disgust.