Proposal/Invoice can instantly produce a number of reports. The options are shown below:
In the example below I have selected All Invoices. Since I always convert invoices into Receipts upon payment, this shows me everything which is outstanding, along with the date issued, etc.
For specialized reports, you may export data in .CSV format for use in spreadsheet programs such as Excel. Select File, Data Export.
Note that items marked "trash" do not show on any reports.