Yes, on some, but thats quite some time ago. Last time was the short crossthechannel ferry to Sicily in a traincar.
Cors. is FRench. It used to be the case that toward Sardinia it was cheaper to use these for some reason.
In general there is not that much to choose, it will depend on route which one goes. There is, or used to be, also the State run, affiliated to the Railways, at that time also FS=delle Stato, but it may well be these now only do freight. From Civitavechchia (north of Roma) to Sardinia.
IMHO there is more difference between ships-also from 1 company as between companies. So it mostly depends on the individual ship/vessel. And these will be tied to a certain line.
Warning: do check carefully if (if applicable) your choice will take just foot-pax. Nowadays many ferries only take people with cars. Such a ferry will also lack easy to find landside connections to nearest stazione.
