This can be anything from Hyperspace in Star Wars, Warp Drive in Star Trek, travel through the Warp in Warhammer 40k or anything else.
I’ve always liked “slow” FTL travel, where going a few light-years still takes a few days or so. I also really like travel through an alternate dimension like in 40k, Event Horizon, Witchspace in Elite Dangerous.
I wanna know your favorite versions, or do you prefer stories that obey the laws of known physics, like the Expanse or Rimworld?
In the later books, the alternative FTL is wild too. The acceleration is so brutal that on every jump, you will be smashed to a pulp and then spend days being put back together.
“Raspberry Jam Delta V” everyone gets inside “Resurrection Creches”. Which just hold your goo for later reassembly.
Funny thing is that, while a similar principle, they’re safer and more ethical than the Star Trek “suicide booth” transporters.
Oh, but they had those too. Imagine a luxury house linked together by instant transporters, so you go to a platform on an ocean planet to poop.