It could be debated what constitutes a true companion—especially when considering those who only lasted for one tour of duty, or who had frequently helped the Doctor but for one reason or another weren’t given the esteemed title (like Rose Tyler’s mother, Jackie), or the ones that never even stepped foot into the TARDIS. With all these variables to process, it would take the sonic screwdriver a couple hundred years to calculate an accurate companion tally.
In any event, while most of these helpful souls can be divide among the best (Sarah Jane Smith, Rose Tyler, Amy Pond) and the worst (Adric, K-9, Mel), there’s also the contingent that can be placed in the category of unsung heroes—those who don’t garner the attention of the favorites but have delivered the goods when the chips were down for the Gallifreyan native—or perhaps, as in one case, good riddance.
*The rest of my article on Five Underrated Doctor Who Companions (And One Scoundrel) can be found here.