In Japan, there are several other types of flour aside from wheat flour.
Shiratama
Shiratama comes from glutinous rice, or mochigome. Because this type of rice is so starchy, the flour is also extremely starchy. It is used most often in desserts, specifically Japanese style ones such as wagashi.
Domyoji
This type of flour also comes from mochigome, but is produced from grinding the rice into powder, rather than soaking the rice then sieving and drying it as for shiratama flour.
Again, domyoji is quite starchy and used for Japanese sweets.
Nuka
Nuka is made from the bran of the rice plant, grinding it to a powdered form. The most common use for this type of flour is as a pickling agent. First, the nuka is lightly roasted then mixed with brine. This results in the bran becoming pulpy, which then ferments. Once fermented, vegetables are added to it to pickle.
Buckwheat
Buckwheat flour is made from grinding hulled buckwheat into a powder, and is commonly used for noodles (soba) It lacks gluten, and is commonly mixed with wheat flour to bind together.