Marvel: Reality Warp Immunity

Layla Miller (Butterfly)
Layla was immune to Scarlet Witch's reality warp, retaining her true memories during the House of M.

Longshot
Because of his probability field manipulation power, Longshot is shielded from the reality-warping powers of others. He was able to resist the reality warping effects of House of M Proteus, while aiding the Exiles.

Meggan Puceanu (Gloriana)
Because of her shapeshifting power, Meggan has some resistance to the reality-warping powers of others. She was able to break free from the power of Jamie Braddock and was one of the few to remember the effects of the Jaspers Warp.

Ruth Aldine (Blindfold)
Blindfold was immune to Legion's reality warp, retaining her true memories and personality during the Age of X. Blindfold also exhibited some immunity to Saturnine's interdimensional fugue.