I’ve done a good amount of this type of work for B2B companies. If you have a B2B venture, trade publications for your target market/industry are a great start. Many run press releases virtually verbatim if they’re relevant to the readership. A local general business publication will also likely be a good outlet. Publication websites generally provide instructions for submitting press releases. To get more substantive coverage, you will need to personally connect with reporters and editors (again, publication websites usually have contact info).
Good luck and let me know if you need more assistance.