There are two main types of accounts receivable, as far as the servicing industry is concerned:

Consumer and Commercial.

Commercial is Business to Business debt. 

We do not handle this type of debt, but we may be able to give you a direction to look if you would like.

Consumer is Customer to Business debt.

This can be anything from local loan companies and banks, to medical practitioners, technical schools, student housing companies, and many other businesses.

Paying accounts versus non paying accounts

Paying accounts are generally sold in a fashion that is called Factoring.   This is not something we do.

Non paying accounts are generally accounts that either are not paying your company, or if you have used a collection agency or attorney, are not paying them.  A common term for this debt is Charge Offs.   These will be further categorized by the number of agencies they have been to, among other things.