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?
Ender’s sagas adresses not only near light speed travel, but also the relativity on communications between the traveling veasels and “stationary” posts via the ansible
I thought the Ender’s game universe was interesting with the instantaneous FTL communication with the ansible, but no FTL travel. They had some tech that could accelerate ships quickly to very near-light speed, which meant you could travel between planets in a few weeks ship-time thanks to time dilation, but years would pass for the people on the planets. So while you could talk with people on other planets instantly, if you wanted to visit them, they’d have to wait decades for you to arrive.
Then later in the books they figured out …
spoiler
that you can more or less travel FTL instantly to anywhere you want just by thinking really hard about it.
The Conquerors trilogy by Timothy Zahn had the opposite - FTL travel but no FTL communication. Smaller ships could also travel FTL faster, so you had a bunch of small ships running around to different star systems essentially delivering the mail. It’s been a while since I read the books, but I don’t really remember it playing a big part of the story other than a way to isolate the battlefronts because once the mail service gets shut down by the enemy you have absolutely no idea what’s happening outside of your local star system.
That is what I said, near light travel, not FTL. Ansible comms where instantaneous (speed of thought iirc), but not when the veasels/ships where in-transit, as they needed to “buffer” the communications somehow, in form of recorded messages. That is why Ender’s journeys took thousands of years, where only a lifetime for his siblings on earth.