We refuse to read/understand the question? Seriously?
Yes, seriously. And respectfully, judging from this reply, you still don't quite understand. Forgive me if I sound too harsh, but it is frustrating to sift through the replies where people question whether the OP is confused, because you don't understand the situation.
The only relevant answer was from colony nofi, who seemed to understand the situation.
Let me try to explain:
These are not neighboring rights.
We don't need a lawyer.
We own 100% of the writer's and publisher's share.
We are our own publisher.
The libraries we are talking about are libraries such as Pond5 (not the traditional type that you are probably thinking of that control publishing). They only take a percentage of the sync licensing fee, but sell lots of them.
I have sold tens of thousands of licenses. Some of them end up in big commercials.
What we need is a publishing administrator. Not a publisher. Not a lawyer. Not a neighboring rights collector. Not a mechanical rights collector.
A publishing administrator would do the job of using services like TuneSat, BMAT, Vivvix/Numerator to try to find unclaimed royalties for our music. Of course for a percentage (like 10%). These often do NOT get reported automatically, like ads in the US for example.
I have used a US-only publishing admin that tracked down a lot of money from ads that were previously unreported (both writer's and publisher's shares).
I have also had UK-only publishing admins for single cases that found thousands of pounds previously unclaimed.
So, what we are after, is someone who could potentially do this for all countries, or at least Europe/US where the royalties are significant.
The recommendation from colony nofi might be what we're after, but I'm asking about alternatives if that doesn't work out.
And yes, of course we COULD do this work ourselves. However, it can be very time consuming and like the OP, I would rather spend that time making music.