AutoCAD has a number of entity types and you might wonder which entities support non-uniform scaling.
As a general rule, the AutoCAD built-in entity classes for entity types that existed before R13 (such as AcDbCircle, AcDbLine, AcDbArc, AcDb2dPolyline, etc.) require that the transformation matrix represent a uniformly scaling orthogonal transformation (if it is not, then Acad::eCannotScaleNonUniformly will be returned). Other AutoCAD built-in classes typically does not have this restrictions.
Also, here is more specific information on commonly used AutoCAD entities:
The following are entities that have a scaling restriction:
AcDb2dPolyine, AcDb3dPolyine, AcDbDimension and derived classes, AcDbArc, AcDbCircle, AcDbBlockReference, AcDbMInsert, AcDbFace, AcDbLine, AcDbPloyline, AcDbPoint, AcDbPoint, AcDbHatch, AcDbShape, AcDbText and derived classes, AcDbTrace, AcDbViewport, AcDbRegion, AcDb3dSolid, and AcDbBody.
The entities that support non-uniform scale matrix are:
AcDbLeader, AcDbMLine, AcDbMText, AcDbOle2Frame, AcDbPloyFaceMesh, AcDbPolygonMesh, AcDbRay, AcDbXline, AcDbFcf, AcDbSolid, AcDbEllipse, AcDbSpline, AcDbImage