
Began in the early '60s in HK. Aside from it's plastic body, it's lens are also plastic. Because of this, the Diana camera is prone to light leaks which leads to film damage causing an effect typically fixed by sealing the seams with light-proof tape. The plastic lens enhances the already low contrast created by light infiltration, creates odd color rendering, chromatic aberration, and blurry images. As well, the image circle only marginally covered the diagonal of the film frame, creating heavy vignetting.
LOMO LC-A
Beginning of the ’90s, and for a few years the Russian factory Lomo PLC has been producing the Lomo LC-A camera, which basically has all of the characteristics of a toy camera (vignetting in particular). But production was stopped, and the camera was all but forgotten until two Austrian students found one at a flea market in 1991 and decided to exploit its marketing potential. They convinced the director of the Lomo PLC factory to relaunch production and negotiated an exclusive contract for distribution with their brand-new company: Lomography AG.
And thus begins the Lomography movement. It is associated with over-saturated and high-contrast images which is the product of film processing rather than the camera itself. Cross-processing is often associated with it. But Lomography is a movement, not a technique, and it was certainly the first to promote camera imperfections as an aesthetic.
HOLGA

But the Holga became popular and was even exported to the West over time, mostly for photo-reporting, for which its low profile was appreciated. Its problems were no longer problems, and now it is not surprising to hear of Holga photos winning awards. Because it is entirely manual, one can create effects, such as double exposure and panoramas, by not winding the film.
ACTIONSAMPLER, SUPERSAMPLER, OKTOMAT
These three cameras don’t have many differences. They all take multiple shots in a set period of time, thus creating micro-images that look like short animated movies. The Actionsampler and Supersampler have four lenses each, while the Oktomat has eight, fitting eight frames into the standard 35mm.
LOMO FISHEYE 2

The effect created, often seen in sport images, can serve many other purposes. But the user should be aware of two major characteristics: strong deformation and light leaks.
source: http://www.smashingmagazine.com/2010/03/10/uncovering-toy-cameras-and-polaroid-vintage-effects/