The best I've designed is below. The reason I specifically called out name is because these are specific system objects that are created t install an not marked as MS Shipped. I could have used '%diagram%' but I would have to worry if anyone in the past or future will call a FCN or SP using that word. Therefore, I called each object specifically so...hopefully the future name won't follow these conventions. There is a likelihood this will happen so periodically reviewing without the filter is important.
and type not in ('D','U','PK','UQ','SN')
and name not like '%diagram'
and name not like 'sp_help%'
and name not like '%diagrams'
and name not like '%diagramobjects'