The Romulans developed a forced quantum singularity for a power source and didn't seem to use dilithium to regulate those reactions - Starfleet knew about it... and could have developed their own version in the proceeding years just because they knew it was possible.
The fake USS Dauntless (which had a Quantum Slipstream drive - all of which Voyager crew scanned in detail and brought back to the Federation) didn't use Antimatter (and by extension Dilithium).
Krieger Waves (never completed - but the research was still there and Enterprise-D recreated the entire station and Krieger Waves experiment which allowed Geordi to absolve Riker) - no followup on that one.
Omega Molecule - Voyager found a way to safely stabilize and control Omega using the harmonic resonance chamber... but Omega Directive prevented them from keeping and eventually using the molecules and so they destroyed them - but the crew retained the knowledge of what they did, and even though Janeway deleted those logs, its possible a security backup was made for Starfleet higher ups to review the data regardless. They may fear Omega, but they're also not stupid to pass up an opportunity to study what the crew did (and besides, plenty of new discoveries in power generation come with potential dangers - that doesn't stop you from finding SAFER ways of pursuing it).
The Borg also don't seem to use Dilithium or Antimatter for power generation.
Both the Enterprise-D and Voyager crews were on board Borg ships and scanned Borg technology in detail. Also, 7 of 9 was liberated from the collective... acquired massive amount of data from her being in the collective second time (in Dark Frontier) and downloaded that data into Voyager's database.
Just to name a few.
I cannot recall all of them, but I think there may have been other instances throughout 23rd and 24th centuries mentioning power sources that did NOT rely on M/AM reaction or dilithium for regulation.
Bottom line is... Trek demonstrated on more than one occasion there are PLENTY of options that go beyond dilithium and antimatter for other alien species... it just never explored them in detail.
It also seems stupid to me to have such a limit in Trek... it never presented itself as such.
Its just lazy writing.
The Trill were also developing wormhole tech in DS9, sans-subspace destruction.
Slipstream needs benamite, which Voyager could synthesize, but it would have taken years to make enough. Obviously the hurdle is not capability, but capacity. A dedicated facility aught to be able to make benamite in far greater volume, as in enough for one ship in less time, or multiple ships in the same time.
The real problem is the benamite destabilizes quickly after use, so the Dauntless must have had some sort of perfected on board synthesis, or stabilization method. Or, if it really only degrades after use, there needs to be enough in isolated storage for multiple trips like the ridiculously huge dilithium room in Discovery.
Seven MIGHT have solved Omega Molecule stabilization. Frankly, I would assume the Federation would have ordered the process attempted again given what happened, and just do it with a holographically, or dumb android, crewed slow ship so the experiment can be done in the already destroyed subspace zone, to avoid destroying more subspace.
The timeship Wells had a temporal transporter with at least galactic range. There's also Scotty's transwarp beaming which would also make a great ship propulsion method, and for all we know is the step up to regular transwarp. Transwarp beaming could be the precursor to temporal beaming.
There's also the catapult thing Voyager used, which used a non-dilithium power, and triaxial warp drive which has no mention of a warp core.
I forgot about dimensional transporters, which are more of a medical question than a technical question. That should be scalable up to ships and interstellar distances somehow.
There is also at least one episode in TNG which mentions a stargate.
In "That Hope Is You", Book curses to Burnham that he can't afford X, Y or Z and has to make do with dilithium. We can't tell whether his ship would be equipped to fly on X if he could get some; or whether he has another ship with X engines that he cannot afford to fly at all; or whether he's saying he can't afford to obtain a ship that would use X, Y or Z.
The likeliest interpretation IMHO is the last one: no, he couldn't fill her tanks with benamite and go to quantum slipstream even if somehow the fuel became available to him. Instead, he would first have to obtain a ship with slipstream engines to go with that benamite. His Nautilus is dilithium-only and doesn't work without it, or with alternate fuels or catalysts or whatnot. And it can only do regular warp.
Timo Saloniemi
Book says he could go slipstream if he had benamite and that no one can make benamite for slipstream, but I explain above why lack of benamite should be BS. He also says no one can do wormhole because the Gorn tried and failed.
