Campy hubs and built wheels come with lockrings for 12t and larger cassettes. campy cassettes starting with 11t come with the 11t lockring. if you purchase wheels built on 3rd party hubs, they usually don't come with lockrings and you have to buy or reuse your own.
and like Shimano, all you need is the cassette tool and chainwhip.

You can buy the lockrings separately. Unfortunately they cost a bit. Everything else as mentioned above