In the Marvel Universe, the name Magneto is most commonly linked to Magnus:
|Magneto (Magnus) - mutant, friend and constant opponent of Charles Xavier and his X-Men, founder of Brotherhood of Evil Mutants, father of Quicksilver and Scarlet Witch|
There are multiple individuals who have used this name in the Marvel Universe.
Magneto (Hunk Larsen) - gained magnetic powers in space flight, left to other planet
There are multiple individuals who have acted as imposters using this name.
There are multiple individuals who have used this name in alternate realities
Magneto (Earth-58163) - powerful mutant, savior of all mutantkind, rules most of Earth