I don't think any of the good item choices outright outshine one another, but I agree that specific items can be found more useful than others, depending on the situation. Life Orb is probably going to be the primarily used item among good players as the damage output complements Carracosta the most among achieving consistent OHKO's on walls and frail Pokemon alike via priority. Liechi Berry, Lum Berry, and as Punchshroom have briefly mentioned, Splash Plate should also be among the more optimal of the choices to consider since they also benefit Carracosta's primary goal in the form of sweeping in one way or another.
As for items like Air Balloon or White Herb, as strange as this may seem to some players, I generally find these choices less superior as they tend to detract away from its ability to sweep, break through wall, or just have poor amount of distribution in general. Dodging Earthquake with the use of Air Balloon may seem nice, but most Pokemon that makes use of this move tend to have losing match ups anyways due to the common weakness of its Water STAB or lacking the ability to deal particularly significant damage to it with the help of Solid Rock. White Herb also sounds, but it doesn't really help out from the ways that it's commonly revenge killed or walled by and likewise it doesn't provide any additional power boost, something that Carracosta really appreciates.
As for items like Air Balloon or White Herb, as strange as this may seem to some players, I generally find these choices less superior as they tend to detract away from its ability to sweep, break through wall, or just have poor amount of distribution in general. Dodging Earthquake with the use of Air Balloon may seem nice, but most Pokemon that makes use of this move tend to have losing match ups anyways due to the common weakness of its Water STAB or lacking the ability to deal particularly significant damage to it with the help of Solid Rock. White Herb also sounds, but it doesn't really help out from the ways that it's commonly revenge killed or walled by and likewise it doesn't provide any additional power boost, something that Carracosta really appreciates.






















