Sometimes companions get to see different Doctors - Sarah Jane, Rose etc, and in multi-doctor episodes we have seen companions with 'other' Doctors. So, can you think of Companion and Doctor pairings which would be cool to have seen. Ofcourse this totally hypothetical.

I would have liked to see Captain Jack with Pertwee, I think they would have had a good flirty chemistry, a little tongue in cheek but at the same time jack would have been very destructive helping out UNIT

Conversely, Zoe with Matt would have been interesting. Super clever assistant paired with flappy hands bumbling man

Bit off topic, but it's quite an interesting fact: Wendy Padbury (Zoe) discovered Matt Smith!

I would have loved to have seen Donna come up against The Eleventh Doctor... she'd have likely have commented on how he'd become even more gangly, and likely joked at his baby-face

Sarah Jane as she looked most recently with 12. obviously for 12's side it's purely based on appearance but I think it would be cool to have a mature doctor with a mature companion, and these two seem to suit, given that they both also have a respectable feel about them. Rather than the doctor often looking like an old/middle aged man running around with a young girl, this combination would fit to the eye and would have people mistaking them for an old married couple.

Also I think if Jack or river were in a hartnell episode, he would have regenerated earlier due to double heart attack

Donna and Nine would have been hilarious together They probably wouldn't get as far as the TARDIS doors due to their constant bickering.

I know we saw them briefly together in a CIN sketch in 1985 but I would so love to have seen Tegan with The Sixth Doctor!

Even from that small sketch you could see on a regular basis that the two of them would simply be at each other's throats from the off!

The other one I would love to have seen is Ian and Barbara with the Second Doctor. I don't know why but I feel the three of them would have a lot of fun together!

Not quite a companion, but what about Capaldi with derek jacobi's master. two fantastic equally matched actors slugging it out.