Modern Who my favourites are Donna and Bill, with a side order of Jack and Nardole.
Classic Who: In chronological order: Vicki, Polly, Jamie, Zoe, Liz, Jo, Sarah, Leela, Both Romanas, Nyssa (though mostly because I identified with her at the time, I don't think she stands up all that well in retrospect), Ace
Some of those are recent discoveries from the randomiser re-watch. What is really striking is how strong the companions were throughout the 1970s in spite of the sometimes odd ideas of the production team (I mean, they clearly designed Jo to be a silly ditzy blonde and yet she's so much more than that and so much of what she does actually undermines that stereotype). Then JNT comes along and until Cartmel appears no one seems to be really interested in the companions.
Re: Ah! Rose!
Classic Who: In chronological order: Vicki, Polly, Jamie, Zoe, Liz, Jo, Sarah, Leela, Both Romanas, Nyssa (though mostly because I identified with her at the time, I don't think she stands up all that well in retrospect), Ace
Some of those are recent discoveries from the randomiser re-watch. What is really striking is how strong the companions were throughout the 1970s in spite of the sometimes odd ideas of the production team (I mean, they clearly designed Jo to be a silly ditzy blonde and yet she's so much more than that and so much of what she does actually undermines that stereotype). Then JNT comes along and until Cartmel appears no one seems to be really interested in the companions.