As viewers of Doctor Who know, different companions bring out different qualities in the Time Lord. While Rose Tyler helped the 10th Doctor get in touch with his romantic side, Martha Jones's unrequited crush just made him feel uncomfortable. It took Donna Noble, a woman he had zero sexual chemistry with, for him to hit his glorious manic-gonzo heights.
What if the various Doctors were paired up with companions from different eras? How would the 3rd Doctor cope with Strax, the warrior clone-turned-gentleman butler? Would the 9th Doctor's psychic burden for destroying his homeland be lessened if he travelled with his grand daughter Susan Foreman instead of a young stranger from Earth?
Some of these combinations would be dream teams. Others would have The Doctor (and probably the viewers) begging the Master for total annihilation of space and time.
10 FANTASTIC!: THE 1ST DOCTOR AND CAPTAIN JACK HARKNESS
While the 1st Doctor was practically an adolescent at a mere 450 years old, he had the body of an elderly man and wasn't as spry as some of his future incarnations. On top of that, his companions were primarily his grand daughter and school teachers. Although he eventually added Royal Navy seaman Ben Jackson to the crew, he really could have used Captain Jack Harkness.
The swashbuckling Harkness, former Time Agent from the 51st Century, would be a formidable ally for the original Doc. He's a proven Dalek fighter who could have kept a protective eye on the others, freeing up The Doctor for more intellectual pursuits. Plus, who wouldn't want an immortal on their team?
9 DREAM TEAM: THE 4TH DOCTOR AND DONNA NOBLE
These two both have stubborn streaks a galaxy wide. Yet, this pairing has a lot of potential. The Fourth Doctor is no stranger to strong willed companions, having shared the TARDIS with fellow Time Lords Romana I and Romana II. And yet, the Romanas' sense of entitlement would occasionally throw the Scarfed One off his game.
Donna Noble is someone this Doctor definitely would click with. Strong willed, yet very aware of her limitations. Her innate sense of humanity kept the 10th Doctor in check, and this Gallifreyan needs that kind of grounding way more than the "Allons-y!" shouting guy ever did. Plus, it's a sure bet she'd share the 4th Doctor's weakness for Jelly Babies.
8 THREE'S COMPANY: BILL POTTS WITH THE 7TH DOCTOR & ACE
It's a no brainer that the 12th Doctor's Bill Potts and the 7th Doctor's Ace would be fast friends. Both young Brits have guy's names. Both have a similar fashion sense. And both call their Gallifreyan mentor "Professor."
Ace and Bill are fearless in their own ways. Ace is quick to take a baseball bat to a Dalek, and Bill is very in touch with her sexuality. Maybe Bill could help Ace come out of the closet? After all, the brash teenager's relationship with Karra had... some subtext. Either way, these two would be tight, and the Doctor would be pleased with their team work. And who knows? Knowing the 12th Doctor's love of the guitar, maybe Bill would surprise the 7th Doctor with that Yamaha SGV-800. They could start a band!
7 LAUGHTER IS THE BEST MEDICINE: THE 8TH DOCTOR AND NARDOLE
When we see the 8th Doctor in "Night of the Doctor," he's a shell of his former self. The Time War between the Time Lords and the Daleks is close to destroying not only the universe, but his psyche as well. When he tries to save a pilot named Cass, she refuses his help because of his planet's role in the conflict. She declares he's no better than a Dalek, and dies soon afterward. The Doctor is so depressed, he decides the universe doesn't needs his services anymore. He swallows an elixir that will cause him to regenerate into a warrior.
This guy needs to lighten up! So who better to keep him company than the 12th Doctor's buddy Nardole? A good natured native of the planet Mendorax Dellora, Nardole's cuddly appearance is destined to put a smile on the face of the most jaded soul. He was also decapitated in the first episode he appeared in so he knows the value of keeping his head in pressure situations. He could also stick around to keep the 8th Doctor's spirits up.
6 BRO-PANIONS: THE 10TH DOCTOR AND JAMIE McCRIMMON
The 10th Doctor had his share of female problems. He and Rose Tyler were madly in love, only to be forever separated in parallel universes. To make matters worse, she shacked up with his clone. Then Martha Jones came aboard. She crushed hard on the Converse-wearing Doc, while he was still hung up on Rose. Things were always awkward.
What the 10th could have used was a full time male companion, though not like Rose's ex Mickey Smith, who just compounded The Doctor's lady woes. Jamie McCrimmon, companion of the 2nd Doctor, would fit the bill nicely. A soldier from mid-1700's Scotland, he's quick with his fists and says what's on his mind. Jamie's simplicity would be a welcome change of pace. Plus, the 10th Doctor must have fond memories of him: he used the name "Jamie McCrimmon" as an alias in "Tooth and Claw."
5 THE WILD BUNCH: THE 11TH DOCTOR AND LEELA
Like fish fingers and custard, there's no telling how this combo would interact. But once the idea pops into your head, you'd sure have to try it! A savage warrior who is actually the descendant from passengers of a crashed exploratory vessel, Leela is always up for action. That's a good for the 11th Doctor, who always seemed to be on the run. And while the 4th Doctor was always making efforts to civilize her, the boyish 11th would probably be content to let Leela's freak flag fly.
A veteran of such strong female personalities as Amy Pond and River Song, the 11th Doctor would be quite at home with Leela's impulsive ways. In fact, it's not a crazy thought to think these iron-willed companions might've shared a relative down the line. And while none of the women in the Doc's life ever warmed up to his favorite fez, it's doubtful that someone wearing animal skins would criticize his sartorial choices.
4 ACERBIC ALLIES: THE 12TH DOCTOR AND ADRIC
At first glance, it seems this pairing could be a disaster: both are rough round the edges, stubborn egomaniacs. But that's what could be so great about it. The 12th Doctor and Adric understand each other. Originally hailing from the planet Alzarius, Adric was a companion for the 4th and 5th Doctors. He was a mathematical genius who could act immature and arrogant. While the 5th Doctor dealt with the teen as best he could, the 12th Doctor's has had more than a billion years to think about his parenting skills. There's a possibility he might have learned something.
The 12th Doctor's gruff manner could occasionally rub Clara and Bill the wrong way. It wouldn't bother Adric, who's also clueless when it comes to dealing with people's feelings. These two could dispense with the niceties and devote their full efforts to protecting all of space and time.
3 DISASTER DUO: THE 2ND DOCTOR AND AMY POND
Amy Pond, AKA "the girl who waited," and the 11th Doctor shared probably the strongest Doctor-companion bond in the entire series. She and the "Raggedy Man" were family. Even still, she had absolutely zero tolerance for affectations like the fez or his stetson. And if she can't cut him slack for a couple of hats, how could she ever put up with the 2nd Doctor's annoying recorder playing?
There's a chance that Amy would eventually warm up to the "cosmic hobo." After all, 2 and 11 did have many similarities - like their love of bow ties. But it's just as probable that if the 2nd Doctor was the one in her life, she'd just assume to stay trapped in the Pandorica.
2 NOT SO FAB 4: THE 6TH DOCTOR WITH YASMIN, GRAHAM, & RYAN
The 13th Doctor is much more laid back than her predecessors: she likes to give everyone a voice, and run things like a democracy. Yasmin, Graham, and Ryan have taken full advantage, always feeling free to chime in with their two cents. The Sixth Doctor does not like to have his authority questioned, and absolutely would not put up with their complaints. The guy was put on trial for the entire 23rd season. He doesn't need their judgments as well!
Even more irritating to him would be having to listen to the saga of Graham's and Ryan's relationship. He simply doesn't have the patience to listen to someone's childhood issues and hurt feelings. And if he had trouble tolerating the opinions of 1980's inhabitant Perri Brown, there's no way he could possibly deal with millennials. The first time Yaz or Ryan smirked "okay boomer," the three of them would be tossed out the police box door.
1 TWO'S A CROWD: THE 13TH DOCTOR AND ROMANA I
As mentioned above, the 13th Doctor doesn't like to "Time Lord" her authority over her companions. Is she were paired up with Romana I, that would lead to a complete disaster. Romana, short for Romanadvoratrelundar, is also a Time Lord. She was ordered by the White Guardian to help the 4th Doctor find the six parts to the "Key of Time." She considered herself smarter than the Doc, and often looked down at him. The 4th Doctor didn't originally like her, but as an arrogant person himself, he knew where she was coming from.
The 13th Doctor would not be so understanding. Always under intense pressure, she's always able to keep her sense of humility. She expects the same from her crew. Romana's histrionics wouldn't fly under her watch. Although it's "bigger on the inside," there's only room for one female Time Lord on this TARDIS.