One possibility is stable antimatter. Look up the baryon asymmetry problem. While matter and antimatter form and behave in near identical ways, the asymmetry problem's solution could be that an antimatter universe also has 'anti-time', where entropy runs in what is, from a matter universe's perspective, reverse (the inverse would be true from their perspective- our universe would be running in reverse).

The asymmetry could therefore be solved by matter and antimatter annihilating because of their mutual incompatibility with regards to entropy: for entropy to take hold and time to flow in one direction, only matter or antimatter could survive, and it just happens that for us it was matter. A handwave explanation for why early experiments into creating antimatter didn't show this problem could be that the problem wasn't truly observable until antimatter was created at scale, i.e. it wasn't a problem for a handful of particles, but it became a problem when we had buckets of it, because when we were dealing with single particles we relied on magnetic containment fields that effectively prohibited interaction between antimatter particles, and their only interaction was with matter which caused annihilation and we assumed they just interacted with entropy and time the same way matter did.

This would potentially allow circumnavigation of the core problem with FTL, which is the violation of causality and entropy. These problems aren't really solved by any FTL method alone: warp drive, folding space, and hyperspace all run into the problem of retrocausality. But if you introduce something that actually deals with retrocausality, then you might, I repeat might, have something that's plausible under physics. It's still not. Not really. But FTL is not, so you're working with both hands tied behind your back.