Hi Andrew,
As Suman mentioned, there is no option to export maintenance plans for the list view. However, you could also explore the option of exporting the same from Data Workbench.
1. Navigate to data workbench work center in HTML5 and click on Export Work center view.
2. And, select the Object as "Maintenance Plan" (you can export all data or selected fields)
3. Click Next and Export Data.
4. Go to Monitor Work center and open the csv file from there. It will appear as the topmost line item or task once it has run successfully.
Regards,
Pavithran