Has anyone created a list of fields that are being used as part of an integration that you can see on a transaction record.. i.e. let's say you have Shopify and you are sending field information from NS sales order - just in a list view see all the fields that are being used as part of the integration (so not the detail - just a view of field 1, field 2 etc)... similar to support case - as a drop-down on the record itself, should you have multiple integrations you can then look to see what's under Shopify, what's under another integration etc?

No, because the fields have no database level relationship with your integration. You could create a custom record and create instances of it containing that info then a SuietLet that allowed you to select the custom records and spit out a list of fields and other details. But you'd need to maintain those records and make something custom.