Folders! You would both have to be good about using them though. When you create a contact list, you can specify the folder for it, and you'd have to get into the habit of doing that. You might have folders for months/years, audiences, etc.
I also think it's really important to clearly name contact lists.
And finally, if you're not reusing lists (since it sounds like you are uploading a new list for every survey), you could occasionally purge old lists just to keep the contact library cleaner.

Thanks. I do use folders but I can only use them for lists and samples I created. When a list and its samples were shared with me, I cannot drag and drop them into a folder.

We use folders as well. However, I am having a hard time trying to find out how to put the lists in folders when you automate. Any ideas?