If you had a wormhole generator, that could be very nasty if not a bit lopsided. Put one end right on the surface of some star, and the other above
whatever you want to get rid of. But that kind of tech is probably too lopsided to make a good story of. (Unless you come up with some epic way to
defeat it before activation. But then it's just another "Death Star" story.)
Likewise a teleporter could be just as mean, depending on what's being teleported. Not just bombs or raiding partys, but nanobots, chemicals, or
biologicals could cause chaos at the target destination. Yet few popular sci-fi storys ever use the device this way.
Throwing a planet seems difficult, and if you could do things at that scale there may be better ways to assault your opponent. And if your opponent
can defend against an assault on a star system, they may be able to deflect this kind of attack as well. However within a system, using a mass thrower
on smaller bodies (like asteroids) seems logical. And has been used to good effect in other works of fiction.
For shorter range, there's your typical energy weapons. Lasers, phasers, and energy bolters and blasters of various sorts. Creativity is in
explaining how they work and making it sound plausible. (One of my ideas is an electro-dynamic induction gun, that's an evolution of Tesla tech that
shoots ball lightning. In which other exotic matter may be encapsulated if the discharge itself is not destructive enough. But working it into a story
is another thing.)
And of course for up-close and personal there's the guided and kinetic weapons that are a seeming obvious evolution of current technology.
If you want to consider something odd, you might go for something that seems innocuous and possibly hard to detect. For example if you somehow figured
a way to direct an interstellar gas cloud at a target, they may not notice what is going on. But then when it starts condensing in their planet's
atmosphere and raining down volatile hydrocarbons upon them...
With advanced technology, weapon spam is also an attack strategy. Consider robotic replicators, that build up elsewhere before homing in on the main
target. Then the trick is defending against a countless onslaught. Are they hackable? Or is there some other unusual weakness?
There could also be chaotic attacks with memetic weapons that disrupt social order (either with infiltration or broadcasts), or releasing technology
that is unexpectedly simple yet very dangerous upon an unadvanced society. This seems to happen in some sci-fi fiction, but on occasion it also