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?
I wouldn’t say it was my favourite FTL but it has some interesting implications.
The artificial wormholes of The Algebraist by Ian Banks. I can’t say too much if you haven’t already read it, but it’s artificial wormholes that have to be transported sublight.
All the new wormholes are of course lovely and high capacity, but much of the network is still the original tiny little ones first installed. So your military at least uses kilometer long needle ships that can fit through these small points.
Think fitting an aircraft carrier through a Stargate.