- Warp drive (Alcubierre engine)
Warping the space-time to travel at FTL speed without being more faster that the light. We can use Alcubierre theory as "lore" or simply using "Warp coils" to generate the warp field that warps the space-time.
- Hyperspace (like B5)
Hyperspace is a high dimension of the reality (Super-strings say that are 11 dimensions or more!), but is "compacted". Travelling there a 1Km will be like travelling 1000Km in normal space. To use it, you must make a portal to it, using a hyperspace generator (bigger thing). Usually only bigger ships have it as need a lot of power and is huge. Small and medium ships relays in a network of fixed portals.
when someone is in the hyperspace, travelling it's easy, as there is gravitational currents, and high distortion, needing beacons to travel safe to know places (the network of fixed portals acts like beacons). Space warface could be happen inside hyperspace.
- Quantum Micro-Wormholes
At quantic scale the space-time is chaotic, generating and destroying all type of space time aberrations in this scale. Some times a micro wormhole from were you are and ends near were you desire to go, will be generate randomly. This is happening continuously. You only need to detect one of this random micro-wormholes and stabilize it and make it bigger. In other word, you only need to wait a short time before a appropriate wormhole is generated. This requires a lot of energy, but gives a very fast FTL way of travelling. But this have a price. If you need a more precise destination point, you will need to wait more time to a adequate wormhole. Plus as the target destination distance increase,s the time that you need to wait for the worm hole increases exponential.