Magneto's Huge Freakin Family
Below is a list of everyone Magneto is related to. It took me a while, but I think I finally got all of them. Though, if you guys can think of anyone else, give me a heads up.
As an aside, God help us all if Polaris ever marries her long time boyfriend Havok. If that happens, the Summers family tree will connect with Magneto's, which will make him related to pretty much everyone in Marvel Universe.