i have several variegated plants that throw white leaves periodically.
My Algerian Ivy has one branch that is ultra slow growing and always has only white leaves on it.
my Spathiphyllum 'Domino' occasionally has some. they don't last long and usually brown at the edges. I tried to separate crowns with more white patches, but they eventually declined or morphed into normal all over variegation.
and finally my Syngonium 'Emerald gem' has some too, but the white ones also decline fast and brown at the edges. the half-white ones hold ok. It needs partial sun to produce more of them.