We don’t have an SDK that searches for PI Tags and PI AF Attributes. Nevertheless, you can develop a custom library that for a given query, it will search for results on both types of servers. I recommend you to use the methods PIPoint.FindPIPoints() from OSIsoft.AF.PI namespace and AFAttribute.FindElementAttributes() from OSIsoft.AF.Asset namespace to get the results from the PI Data Archive and the PI AF Server respectively. Those methods are available on PI AF SDK 2.5 or 2.6 with Rich Data Access.
As you want to use within VBA, you will have to use AFWrapper in order to have access to PI AF SDK objects.
Hope it helps!