There are three ways to find companies that report to D&B:
1) pay a company that provides corporate credit building services
2) contact any company you are interested and ask the business billing or credit department (stay away from sales)
3) pay Dun & Bradstreet to build your PayDex score
Bonus way is if you can find an intermediary or someone with a database of credit pulls you might be able to find some company names. I've found a few at creditboards.com under business credit: NEBS, ULINE, VIKING, etc. but almost all these companies are overpriced for small businesses.
There is no quick fix for corporate credit and it's one of the most closely guarded and monopolized data in the world!!!