2 suggestions of something that would be helpful.

Possibly quite easy would be to add a not checkbox to the search field itself. Specifically useful to find orders that do not contain a certain product. I imagine that it is possible that could be a simple implementation.

A second request is to add additional layers to refine the results. Right now we have Order Status AND country or state or payment method. Would be quite nice to have even one more layer. For example, searching by product ID A, and then possibly have operators (AND, OR, etc.). Basically just taking that core search filtering and expanding it out to be a little more robust.

Hope that made some sense and maybe simple to add :)