This module scrapes the SetCronJob IPs from their website and makes them available as a list. If you are using this module, I highly recommend subscribing to the SetCronJob Notification emails regarding changes to this list at http://eepurl.com/cxEQcL. Since this module dynamically generates the list, it won't be updated alongside updates to the SetCronJob list updates.
[The SetCronjob service documentation](https://support.setcronjob.com/hc/en-us/articles/219802207-SetCronJob-IP-addresses-list) points to the following text files for IPs that they use: