With the new Patch yesterday, we got new content in the form of a post-game party, thrown by Withers! I've seen people talk about a potential plot hook with Karlach for a DLC down the road, but what other potential plot hooks have you seen?
In my epilogue I had Lae'zel and her mission to talk to with the big important Githzerai guy whose name I cannot remember or pronounce, Gale inviting you to his magic school to talk with his students, Karlach and Wyll going to fix her engine and me trying my best to resist the urge to devour the brains of my fellow companions as a mind flayer (that one was a big surprise when it happened!). With how many possible permutations to the ending there are, I think the most realistic one for a DLC is the straightforward Karlach + Wyll (and possibly you) going to fix her engine, at least that one only has like 4 possible outcomes from what I recall (who goes with Karlach, and if Tav is a mind flayer or not).
Yeah, some sort of Karlach+Wyll DLC for seems the most obvious to me from what I've read.
Going to Gale's magic school could be fun too, either as its own DLC or as a little side thing in another one. I'm sure a school full of Wizards could cause some problems that my character could be called in to help solve.
I was working under the assumption the player kept Karlach alive and un-mind flayered, it's possible she never even made it to the end because Wyll killed her or the player committed some good old tiefling genocide and she left. The very idea of a DLC is honestly incredibly unlikely, but if one did happen and it wasn't just some unrelated story, resolving Karlach's engine troubles is probably the least convoluted one to implement.