Thanks for the suggestion Monika. We are looking into 2 features to help here:
This feature has been implemented in our September 2015 release. You can now do on-the-fly incremental searches on campaigns and on statistics reports. Automatically search subject, campaign name and send-to audience.
Monika S
I think a labeling system would be ideal in this case. That way we can apply multiple tags to a campaign and then sort by those specific tags when we want to see a certain subset of emails. I'm sure those that have hundreds of campaigns would appreciate a dynamic ability to file and sort them as well.