The eigenspace of fraud
Interesting discussion of the basic types of fraud at Making Light: here, and a followon here.
1. Simple misrepresentation.
2. Using high-pressure tactics to confuse or intimidate the victim.
3. Shell games, sleights of hand, and switch-and-retraction cons: the pigeon drop, the Jamaican switch, Three-Card Monte, etc.
4. The Spanish Prisoner
5. Ponzi Schemes
6. Pyramid schemes
7. Selling information about, or access to, uncommon opportunities
I would add selling a dream. The con man sells people on an appealing dream and convinces them to spend time and money on it. The details determine whether this is a con, a religion, a self-deception, or an honest endeavor. For honest endeavor, consider someone who convinces a town to set up a community garden. For con, think of someone who convinces people to pool money to buy a farm and start a co-op and ends up owning the farm. For religion, think the televangelists that live in mansions built with their followers dough.