Which states have debt collector licensing requirement?

[Bob Malecki]

I was just researching WA for debt collector license requirements and found the article linked below, summary sez:

" Who Is a Debt Collector Under Washington Law?
The definition of a debt collector under the Washington collection agency law is similar to the FDCPA’s definition. Those who are in the business of collecting debts on others’ behalf are covered, but original creditors are not. The following do not need to be licensed.

Original creditors. Original creditors and other creditors who do not regularly collect debts are not required to be licensed in Washington. For example, a small business does not need to comply with the Washington collection agency law when the its owner contacts you regarding a debt (assuming it is not in the debt collection business, of course). Similarly, financial institutions, realtors, and your landlord do not need to be licensed. "

https://www.nolo.com/legal-encyclopedia/washington-collection-agencies-law.html

What other states require a license for those of us who are NOT collecting on other's behalf?