Only a few come to mind as "legendary."
I am not going on hopes and dreams. Too many people listing what they want and not what is in the realm of realistic.
Van Halen
Motley Crue
Queen (I know its being done, I would rather it come from a mainstream company.)
Also, and I reluctantly say this, Def Leppard.
Would I love a Black Sabbath, hell yeah. You give me a Tool pin that is dark and twisted and I'm all over it.
Seems like bands from the 90s are ignored which leaves most suggestions from that era an improbable request. Now if someone gets some balls and drops a Nirvana, Pearl Jam, etc. and it takes off, then you open the doors to a whole new era of music pins. (Speaking of Doors, yes please.)