The First Doctor, Steven, and Oliver

Oliver is a real rarity in Big Finish: a brand-new companion inserted into the earliest stories. Original companions are unusual, but not unheard of, but this is the only one who was created in the Companion Chronicles, instead of in the Main Range. The stories after that are the Doctor traveling with just Steven, which is technically what they’re doing in “The Massacre,” but that period tends to be overlooked, since it didn’t last very long.