Agree with above; likely a gastropod(s). It's a stretch of my imagination, but if those specimens are Cambrian origin, the coiled shape in Frame 3 upper right slightly resembles Pelagiella.
Without a scale I would not comment on potential families or groups. That is a basic palaeontological requirement before any advice can be given. Equally well, there should be some indication of what formation/member this is from, or do we assume that it is a randomly collected lump of grey limestone(?) from somewhere in Italy.