Many companies keep databases of consultants for their customers. This makes sense, especially for vendors of sophisticated products. When a potential customer comes to one of these vendors, the customer is often concerned about training. How will this the training time affect the project schedule? How much will it cost to train their engineers? If the vendor can produce a list of consultants who can start right away and need no additional training, they have a good chance of lessening the customer's concerns, thus increasing their own chances of a sale. So if you've worked with a particular vendor's products, talk to them. Some consultant databases consist of a list that the sales reps keep in their back pockets. Other companies maintain large, detailed databases accessible from the Internet. Both types of databases require little maintenance by you and can increase your prospects of finding work.