Anionic surfactants are said to clean better than nonionic surfactants (no charge) because anionic surfactants use a negative charge to remove oil and dirt from the surface of skin and hair.
Anionic surfactants
Sodium Cocoyl Glycinate (aka GentleFoam SCG) [Ecocert/NPA approved]
Sodium Cocoyl Isethionate (aka BabyFoam SCI)
Sodium Lauroyl Sarcosinate (aka EasyFoam)
Nonionic surfactants
Polyglucose/Lactylate Blend (can be combined with mild anionic surfactants)
Decyl glucoside
Coco Glucoside (can be combined with anionic surfactants)