When it comes to this trope, I can give a great example that is also not mentioned. The Doctor’s companion, Clara Oswin Oswald, who helps the depressed, lonesome Doctor get a new thrill for life in The Snowmen. She is also a caregiver, a nanny, and the real Clara in modern day London happens to also be a caregiver.
Clara is the Manic Pixie Dream Girl.
Samantha Carter was the Smurfette, while Teal’c was the Token Minority.
Constantly played straight and averted in Doctor Who, thanks to the ever changing nature of the show. Because the Doctor is male (although, he could regenerate into a girl, theoretically) writers tend to balance him out by having a female companion. Extra companions will occasionally be brought on, but their gender in completely random. Examples of multi-companion crews have been:
◦First Doctor; 50/50 for the first while. There was the Doctor and Ian, plus Barbara and Susan.
◦Second Doctor had for a while 2 boys (the Doctor and Jamie) plus one girl, Zoe. Another girl, Victoria, occasionally joined them.
◦The third Doctor was a bit of an odd case. Set on Earth, in a male dominated military organisation, there were mostly guys around. Main cast members, however, were the Doctor, The Brigadier, Harry Sullivan, and Sergent Benton, with Sarah-Jane Smith, Dr. Liz Shaw and Jo filling in the female roles.
◦Fourth Doctor companions were Sarah Jane Smith, fellow Time Lady Romana, Leela, Tegan the air-hostess, with the guys being Adric and the robot-dog K9.
◦The Fifth Doctor again had a string of mostly female companions, such as Peri and Tegan. There were guys, however, such as Adric, Turlough and the robot Kamelion.
◦The Seventh’s Doctor only permanent companion was Ace.
◦For the majority of Nine’s run Rose Tyler was the only companion, although the very popular Captain Jack Harkness came on near the end. By the end of the Russel T. Davies era all the companions from the period came back, including Martha Jones, Donna Noble, Sarah Jane Smith and Jackie Tyler for the girls, with the guys including Jack and Mickey.
◦The Eleventh’s Team TARDIS could be considered 50/50, so far: You’ve got the Doctor and Rory, but also Amy and River.
I can definitely say that this is Amelia Pond during the first half of Series 6 had a Mystical Pregnancy.