In Black/White, there is a new family of Electric pokemon with the ability levitate, but are there any others, because electric and flying gives it a weakness to rock and ice!
Nope, the electric Eel family is the first set of pure Electric-type Pokemon with the ability Levitate. The next closest thing would be to get a Zapdos or Emonga, which are Electric/Flying types.
Actually, the move Magnet Rise could be used to make a purely-electric type pokemon immune to ground types as well.
Rotom has the ability levitate and is an electric ghost type.