Is there a way I can list all people in my tree who have incomplete sources?
Who has incomplete sources? That would be all of them! There seems to be no end to new records becoming available that can be used as sources.
We do, however, a way to see who of the direct ancestors for a person, ourselves or any other person in Family Tree, have a higher or lower number of sources by using the fan chart. Pick yourself or any relative, go to that person's fan chart and choose to display Sources:
Now if you really mean a way to see unattached hints, select Research Helps on the fan chart to see them:
However, if you actually mean people who, when you look at their sources, have the notation "Unfinished Attachments," then usually the fan chart with hints will help because those unfinished attachments are often spouses and children.
If you mean something else, please explain in more detail exactly what you are trying to find regarding sources.