Why is Rory always being dissed?  From the producer, refusing to put his image in the doctor’s memories before regeneration, to no one ever talking about him. He was a brilliant companion, who often put the doctor rightfully in his place, and helped him see the bigger picture of things. It irritates me that so many people disrespect that character.

Also, let not forget Catherine Tate nailed in her standalone episode turn left where she changes time by turning right or left can't remember. I remember reading and seeing videos that the producers didn't think she would be able to carry that episode alone, at least in a serious way, since she is from a comical background, but after they saw her they changed her mind because she was able to play role in a serious manner.

Uh… Ian Marter (Harry Sullivan)? I get that it’s easy for him to fade into the background when he’s standing next to the peak pairing of Baker and Sladen, but he was traveling with the Doctor for over a season during, as you mentioned, the height of the classic era’s popularity

I watched all of Peter Davison's Doctor stories especially Terminus and never saw anything wrong with Nyssa kissing Peter's Doctor goodbye. When anyone thinks about it Tegan lost her aunt to the Master just like Nyssa lost her dad, stepmother and her home planet to him - rendering her an orphan - and Adric lost everyone including his brother to the Marshmen. Is it any wonder why Nyssa showed some affection for the Doctor, considering he, Adric and Tegan were in some sense the only makeshift "family" she had?!

No Rory or Nardole? Aren't they Companions too? Especially Rory.

Harry Sullivan is a glaring omission here. The very first series I saw was The Ark In
Space and I had no clue what Dr. Who was or its history. Continuing to watch the show in chronological succession made me a huge fan, but I assumed that Sarah Jane and Harry were THE companions and I was sorry to see him leave.

Liz Sladen, is my fave by at least a parsec.
But, I liked Romana Mk1 and Mk2 a lot. As for the blokes, Fraser Hines as Jamie the Highlander - no question.

William Russell was actually supposed offered a third season but Jackie Hill wasn't.  But he wanted a raise and the BBC said no. THAT'S why he left. Also it's pronounced "Adrian Hill" (See Doctor Who Children in Need 1985!).  As for Anneke Wills she was asked to stick around originally but out of loyalty to Michael Craze she left when he did.  Early drafts of some of Victoria's stories plus some unproduced scripts list Jamie and Polly as companions!

4:34 Fun fact: Peter Purves is currently the oldest living companion actor.

I would love to see a video on how every companion actor got cast.

It's always bugged me that we never find out how Mel ended up with the Doctor in the first place. She just appears as if she's already been travelling with him a while.

I can see why Jack Barrowman wasn't officially a companion he was just a recurring character like River...  But Nardol!?  Matt Lucas was totally a companion for the same series Pearle Mackie was!

I preferred Rory and Amy together as companions over just Amy.
Would have liked to have seen Arthur Darvil get more of a mention.
And Matt Lucas too.

Even though it wasn’t really Bill, just the Testimony’s copy made from her memories. I love her expression when the First Doctor meets Peter Capaldi’s Doctor and the Testimony are giving that monologue about the man the Doctor will become. The music in that scene is absolutely incredible. Just look at Bill’s face she’s in complete awe, impressed and excitement, and taking in everything the Doctor has done with awe.

As much as I love Zoe, I don't think the show would have nearly been as successful if she had continued into the 3rd Doctor's era. What makes Spearhead from Space a great introductory episode is the lack of reliance from what came before.

Did you know (probably) that Diana Gabaldon, the author of The Highlander named her character Jaime Frazer after Jaime in the Dr. Who series.  Loved hearing that from Gabaldon herself.

there's one heck of a difference between Old Skool and Modern companions including their episodic lifespan

Arthur Darville, Matt Lucas, Camille Corduri, John Barrowman, Bernard Cribbins and Alex Kingston should have been mentioned, too :-)

you forgot to mention that nicholas courtney also played space security agent bret vyon in the daleks' master plan during the first doctor's run, there was also sara kingdom (jean marsh) who was also introduced in the same serial as nicholas. then we have sargent benton (john levene), and mike yates (richard franklin) who were recurring roles during the thrid doctor's run. then we ian marter who played surgeon-lieutenant harry sullivan during the fourth doctor's first two seasons. we also got k-9 (voiced by john leeson) throughout the fourth doctor's run. we got kamelion (voiced by gerald flood) during the fifth doctor's run. you completely left out doctor grace holloway (daphne ashbrook), the eighth doctor's only companion on screen. then we have adam mitchell (bruno langley), captain jack harkness (john barrowman), mickey smith (noel clarke), astrid peth (kylie minogue), and wilfred mott (bernard cribbins) of the rtd1 era, with jackson lake (david morrissey), lady christina de souza (michelle ryan), and adelaide brooke (lindsay duncan) are more contested as companions for the end of the tenth doctor's run. of corse we have rory williams (arthur darvill), [how can you forget this one?] river song (alex kingston), craig ownes (james corden), john riddell (rupert graves), queen nefertiti (riann steele), brian williams (mark williams), madame vastra (neve mcintosh), jenny flint (catrin stewart), commander strax (dan starkey), and nardole (matt lucas) of steven moffat' era.

The companion led story's are primarily in the rebooted version.