Here’s a helpful list of common grifts, provided by the Inspector General of the Department of Defense. For example:
Fictitious Vendor: In a weakly controlled environment, an employee with procurement responsibilities, or in accounts payable, or an outsider, can submit bills from a non-existent vendor. Normally fictitious vendors claim to provide services or consumables, rather than goods or works that can be verified. Dishonest bidders also can submit “bids” from fictitious bidders as part of bid rigging schemes.