When creating a List in Planning Center People, there is a new option to find people scheduled (or last scheduled) in the next amount of days, weeks, or months.
For example, this allows you to find everyone on your teams scheduled within one week of today that are unconfirmed. You can set the list to automatically refresh each night, and even perform automations on people that have just been added to the list.
All this and much more is available in our free product, Planning Center People. If you don't have access, ask your Organization Administrator to add you.