Explosive weapon types and the science behind using them is a big list but if it works in the real world it will work here.
http://www.projectrho.com/rocket/rocket3x.html
http://www.projectrho.com/rocket/
I <3 this site when it comes to science bits about how things would work in space.
In this setting anti-matter is used a lot and it basically works by an anti-particle and a particle canceling each other out converting their mass into energy ( E = mc^2, which is a shit-ton of energy). Of course drawbacks of this include storage and inefficiency of use. Assume a brick of anti-matter and a brick of matter collide. Where they impact there will be a large blast which is perfectly placed to push the remaining matter and anti-matter away from each other.
Of course there are chemical explosives that release chemical energy when they are triggered.
There are atom bombs that use fission, slamming heavy things together to release energy from individual atoms.
And fusion, which compresses lighter elements into a denser element in order to extract energy.
There are also kinetic detonators which are basically anything that moves really fast. At any serious fraction of the speed of light an object is going to be carrying enough energy to cause a big explosion when it hits another object, more than enough to break any chemical bonds that either object may have.
There is also Aether, which for the most part just causes energy to come into being (in exchange for increasing entropy in the universe IE: taking some time off its lifespan) and that energy will hit whatever is nearby which will in turn cause everything to be pushed away and explode.
Though your best bet may be to poke around on the wiki:
https://wiki.stararmy.com/doku.php?id=li ... ip_classes
and
https://wiki.stararmy.com/doku.php?id=military_equipment
to see what some of the things in use are.