Akaname Creatures that clean bathrooms with their tongues. See Wikipedia.
Bakeneko A cat with supernatural abilities, sometimes possessing a tail split in two (in which case it is called nekomata). Kirara from the anime InuYasha is a bakeneko, as is the pokemon Espeon. See Wikipedia.
Baku A creature that eats nightmares, and is similar in appearance to a tapir. The pokemon Drowzee and Hypno are baku. See Wikipedia or Everything2.
Fu (or Foo) Dogs Chinese Imperial guardian lions. See Wikipedia or Everything2. Can also refer to Pekingese dogs. Also, there is a talking Shar-Pei in the cartoon American Dragon: Jake Long whose name is Fu Dog. I don't know that there's any relation to either Imperial guardian lions or Pekingese, but I thought I'd mention it, anyway.
Gaki Hungry ghosts. A kind of vampire described in Japanese Buddhism (also called Preta), they may feed on things like blood, feces, or corpses. See Wikipedia.
Hanyou Half human, half demon. The anime character "Inuyasha" is a hanyou. See Wikipedia.
Harionago A youkai woman with hair she can control with her will, to use as a weapon. Yura from the anime "InuYasha" is a harionago (though she might also be considered a tsukumogami). See Wikipedia.
Hitodama Souls of the departed which appear as glowing spheres. See Wikipedia.
Jiang-shi Chinese vampire. Goes by several other spellings, such as Chiang-shi or Kuang-shi. See Wikipedia, TV Tropes, or Everything2. A Jiang-shi appeared in one episode of the cartoon Jackie Chan Adventures.
Kaiju Monster. There are many Japanese kaiju movies. See Wikipedia, TV Tropes, or Everything2. See also Kaiju Big Battel on the arts & entertainments page.
Kappa A kind of Japanese water imp. Also the inspiration for a cucumber sushi called kappamaki (see food page). Kappa somewhat resemble turtles, and like to suck out people's insides. But they can be defeated by making them spill the water which rests in a bowl-like indentation on their heads. Or they can be bribed with cucumbers. See TV Tropes, Wikipedia or Everything2.
Kasa-obake Paper umbrella monster, a type of tsukumogami. See Wikipedia.
Kirin Mythical creature which is a cross between a dragon, deer, and lion. Very lucky. In China it is called qilin (see Wikipedia), also called Chinese unicorn. The Japanese name, Kirin, can also mean giraffe. See Everything2. There's a Japanese beer named for the creature (see foods & drinks page).
Kitsune Fox youkai, often possessing nine tails. The pokemon Vulpix and Ninetales are kitsune, as is Shippo in the anime "InuYasha." There's also a kitsune locked inside the title character in the anime Naruto. See TV Tropes, Wikipedia or Everything2.
Nekomata See "bakeneko."
Ningyo A fishlike creature or mermaid, which may have a monkeylike face. See Wikipedia. May also refer to traditional Japanese dolls (see stuff page).
Oni Japanese word for demons or ogres (which may be good or evil). See Wikipedia or Everything2.
Rokurokubi Beings (usually female) that can stretch their necks to impossible lengths. See Wikipedia.
Shikigami Protective spirits which can be summoned (or created) by onmyoji (people page) or Shinto priests and priestesses. both Kikyo and Tsubaki from the anime "InuYasha" created shikigami. They're also frequently used in the anime Kekkaishi. See Wikipedia.
Shinigami Death gods, or "soul reapers," seen in anime such as Bleach, Yu Yu Hakusho, Death Note, etc. See TV Tropes or Wikipedia.
Shojo Japanese for "orangutan" or "heavy drinker," this can also refer to sea spirits with a fondness for alcohol. Derived from the Chinese creature xing xing ("live-lively," a mountain or forest creature). I think the first time I heard of this creature was in an episode of Supernatural, though it didn't really look apelike in that show, as the creatures should. (Shojo is not to be confused with shoujo, which means "young girl.") See Wikipedia.
Tanuki A shape-shifting raccoon-dog. Hachi in the anime "InuYasha" is a tanuki. See TV Tropes, Wikipedia or Everything2.
Tengu Japanese goblins, which may be benevolent or malicious. Most often they would punish arrogant monks, priests, or samurai who misused their power. May derive from the Chinese Tien Kou (or Tiangou). See Japanese Buddhist Statuary, Wikipedia or Everything2.
Tsukumogami Spirits that originate from objects which have come to life after becoming 100 years old. See Wikipedia.
Yosei Fairies. Today's concept has been influenced by Western mythology, but they were more traditionally depicted as birds. See Wikipedia.
Youkai Japanese word for demons or spirits (which may be good or evil). Most of the creatures on this page could be called youkai. The term is used alot in the anime "InuYasha." See TV Tropes or Wikipedia.
Yuki-onna Snow woman. A beautiful woman who usually appears on banks of snow, and who may freeze people to death or may seduce young men (and then perhaps freeze them to death). See Wikipedia or Everything2.
Yurei Japanese ghosts, restless spirits. They typically wear white clothing and have disheveled black hair. Yurei may be seen in movies such as "The Ring." See Wikipedia.
See also: religion, philosophy & medicine.