Cancellations on genuine stamps are very rare .In addition to the 21 covers which have come to light over the last 150 years there are a handful of loose stamps which have been judged to have seen genuine usage. The most common obliteration is the Suez diamond of dots with the figures 5129 in the centre. Others include a rectangle consisting of a series of lozenge shaped dots in the formation 6x8 or a single or double pen stroke with or without a manuscript date.
When it comes to the forgeries it would seem that anything goes and a wide variety of bogus cancellations abound. I think that it is fair to say that any loose stamp bearing a cancellation other than one of the four mentioned above is certainly a forgery whilst any example that does bear such obliteration should be treated with considerable suspicion until authenticated by a knowledgeable expert.
Concentric circles, circular date stamps with or without a place name, usually Suez or Port Said, are common. Also seen are a variety of Arabic obliterations, which would appear to have been derived from coins or seals
A small selection of obliterations that are commonly encountered is illustrated below.