This doesn't quite do what you're asking because that could get COMPLICATED pretty fast, but this allows you to select part features, and will select all faces that were created by those features. Give it a go and see if it works for you. However if you placed multiple chamfers or did multiple extrusions at the same time it will grab those too.
To use this tool, select all features you want the faces of and when done press escape.
Sub Main
Dim oDoc As PartDocument = ThisDoc.Document
Dim oFaces As FaceCollection = ThisApplication.TransientObjects.CreateFaceCollection
Dim oFeatures As New List(Of PartFeature)
Dim oFeature As PartFeature
Dim oHLS As HighlightSet = oDoc.CreateHighlightSet
Do
oFeature = ThisApplication.CommandManager.Pick(kPartFeatureFilter, "Select Feature")
If oFeature Is Nothing Then Exit Do Else oFeatures.Add(oFeature)
Loop
For Each oFeature In oFeatures
For Each oFace As Face In oFeature.Faces
oFaces.Add(oFace)
Next
Next
oDoc.SelectSet.SelectMultiple(oFaces)
End Sub
If the items you would be using this on look exactly like the feature shown in the image there might be an easier way of going about it. Let me know if this works for you or not.