>>38447742SS is the objective best choice. The whole point of abbreviating a word is to shorten it, if you're not picking the shortest option you might as well type out Sword and Shield.
Including the "and" in the abbreviation is pointless, and only exists for those retards who would actually get confused if people mean Sword and Shield or just Soul Silver on its own. Any grown person should be able to tell which is being referred to by context. The only reason it was included with Sun and Moon was because "funny S&M joke". Notice how nobody says S&M now that Ultra Sun/Ultra Moon have come out and everyone just says SM or SM/USUM.
SwSh is easily the worst on the list, though. Anyone who uses it is absolutely guaranteed to be a redditor who's unironically concerned that SS might sound related to nazis.
>>38447779This is only marginally better than SwSh, but is still bad.
