Which is the right design pattern can be used for this below scenario

Can you someone suggest, which is the right design pattern can be used for this below scenerio?

Function : GetDatasource(string[] Placeholders)

Considerations are

• Flexible to involke service to get the data (each service response data type is different)
• Flexible to extend or add new service call at any time
• All the service calls should be parellel
• what should be the recommended datatype of this GetDatasource function?