Marking Symbols?

Good day,
I am designing a computer chassis and I need to do a silkscreen on the rear panel.
I know that there are standard symbols for keyboard, video, mouse, USB
I am unfamiliar with who the governing body of the symbology is or where I might obtain artwork that I can cut and paste into the silkscreen artwork.
Can anyone point me in the right direction please?
jimB -------------------------------------------- JimB -------------------------------------------- my SPAM defense: Replace all the X's in email address with M
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