I've posted about this previously, but I submitted Double Witness (the book Harlequin bought) to the MUSETRACKS Agent Shop last year. My book received a partial request from an agent which didn't result in landing said agent, but it was a great experience.
If you're looking for an agent/ fun pitching practice, check it out here!
And, to note, if you pitch and aren't picked, consider submitting via the slush pile. What isn't right for one agent doesn't mean not right for another agent / editor.
Let me know how it goes!