Well, let's go to the world record speedrun of Pokemon Black.
His ending team before catching Reshiram is Emboar, Pansage, and Woobat, which means it was practically a solo run with Emboar using Pansage for cut and Woobat for fly.
If you didn't know, the only time an hm is needed for Pokemon black is one use of cut to enter the dreamyard. That's it. Emboar can only learn strength, but is by far the best battler to counteract the gym leaders, beating 3 of the gyms with type advantages, and 1 elite four member, as it is the only one of the started that is dual typed.
So that means that the best team to speedrun Pokemon black with is.... Drumroll please.....
And some hm slaves.
Here's the full video for reference. Hope I could help!