Loading contacts provided by sales - need best practices

Our sales team have provided us with contacts that should start receiving marketing info.  These contacts are not from any campaigns but just contacts directly from sales. 

Does anyone have any advice on template to use for these types of contacts to load into Marketo? I hate to use just general, First Name, Last Name, email, etc.  We also have list upload templates that has the “lead source” but that field is tied to the lead source in CRM so doesn’t offer an option like “Contact Provided by Sales.”

I can create a new template for scenarios like this but looking for an example or best practices on this. 

Thanks,

Niti