Whether it is Project Daedalus or Breakthrough Starshot, there are interstellar spacecraft concepts aplenty, but which seems the most plausible to you?
I’ve always been fond of Starwisp, but I don’t know enough to say whether it’s more plausible than the others you mention.
FQ isn’t really the right subforum for this, but do you mean what propulsion will we use, or what will the non-human crew be like?
Given that it already exists, the most plausible one is Voyager.
[Moderating]
There is factual information available, but you’re right that the question is ultimately speculative. Moving to IMHO.
None of our current concepts are even remotely plausible.
If you mean “Which science fiction author came up with the best-sounding technobabble?” that’s an entirely different question.
As with your last question about spacefaring, you may as well ask the folks who were building sailing ships for Christopher Columbus what’s their best concept for a powered airplane with intercontinental range. Any answer they might give would be nonsense versus what actually will be invented centuries hence.
That’s how far along we are on interstellar spacecraft.
The idea of laser powered tiny craft always seemed pretty plausible to me. A tiny (nano technology based, but nothing to crazily beyond what we can create now) space craft with no fuel on board powered by an external laser pointing at it (from outer space not the surface of a planet). The maths of getting to a significant percentage of light speed are quite reasonable, and don’t require stupid amounts of energy.
It’s not something thats going to happen in the next few decades but it’s not a completely ridiculous thing for humanity to build one day, if we avoid wiping ourselves out.