Note: Most of these require Skill Swap/Baton Pass.
Actual
Tynamo, Eelektrik, Eelektross - 0 Weaknesses with Levitate
Any Electric Type - 0 Weaknesses with Levitate/Air Balloon/Magnet Rise
Wooper, Quagsire, Marshtomp, Swampert, Barboach, Whiscash, Gastrodon, Palpitoad, Seismitoad - 0 Weaknesses with Sap Sipper
Stunky, Skuntank, Drapion - 0 Weaknesses with Levitate/Air Balloon/Magnet Rise
Forretress, Scizor, Wormadam-T, Escavalier, Durant, Genesect - 0 Weaknesses with Flash Fire
Mawile, Klefki - 0 Weaknesses with Flash Fire while under effect of Air Balloon/Magnet Rise
Numel/Camerupt - 0 Weaknesses with Storm Drain/Water Absorb while under effect of Air Balloon/Magnet Rise
Chinchou/Lantern/Rotom-W - 0 Weaknesses with Sap Sipper while under effect of Air Balloon/Magnet Rise
Theoretical
Steel/Poison Type - 0 Weaknesses with Flash Fire while under effect of Air Balloon/Magnet Rise
Source 1 | Source 2