Boy oh boy, he'll lock them down
Generally, theyre artifacts that dont do very much by themselves, but if you tap creatures with total power equal to or greater than their crew cost, they become artifact creatures with the power and toughness displayed in the bottom right of the card
There are fourteen in total: Tauros Skitty Delcatty Fletchling Hawlucha Pikipek Trumbeak Toucannon Yungoos Gumshoos Stufful Bewear Oranguru Komala These are all the Item cards in Celestial Guardians
As for Standard, I played Damnation in my comeback tournament, Regionals 2007
Scalpers, as they are referred to, buy massive quantities of limited releases like this, which limits the amount of product that gets into the hands of players who actually want to use them
Surveil Rules To manipulate some of the cards on top of your library, sending some of them to your graveyard and rearranging the rest