One popular creepypasta anime story is 'The Red Room'. It involves a disturbing and mysterious room that appears in various anime settings, often associated with death and horror. Another is 'Kuchisake - Onna', which is based on the Japanese legend of the slit - mouthed woman and has been adapted into some really creepy anime - inspired tales.
Creepypasta anime stories are usually darker. Regular anime stories cover a wide range of genres like action, romance, comedy etc. But creepypasta ones focus on horror, the supernatural, and often have disturbing elements. For example, a regular anime might have a hero's journey, while a creepypasta anime story could be about a character being haunted by a malevolent spirit.
There's no precise count. Creepypasta is a genre that's very popular and evolving, so the number of stories is ever-growing and can't be accurately quantified.