I hear fetchlands are playable. Comparables include Dismember, Snuff Out, Disfigure ... probably useless because Mental Misstep exists.
Also Wastelands, Stip Mine, and Ghost Quarter. I could definitely see this being played in the Eldrazi decks that are playing pain lands a-la Caves of Koilos or Urborg, Tomb of Yawgmoth.
If you know or think your opponent has this card in hand, it could make combat much trickier. I'm less likely to attack into a chump blocker with my big dude when their chump block activates this card.
Is ... fragmentize unplayable because of misstep?
I don't think that's a good comparison. The primary use case for any anti-artifact card is Workshops, which tend not to play Mental Misstep.