The Pirate Planetin Doctor Who, a hollow planet that can materialise around another planet, strip all its valuable minerals, and reduce what’s left to a tiny supercompressed ball.
If we’re branching out from movies and TV to other media:
One of Asimov’s first stories, “The Weapon too Terrible to Use”, tells of a device about the size of a pen that emits a narrow cone of nigh-limitless range, which scrambles the brain of anything in its area. Fire it from far enough away, and you can turn an entire planet wort of people into drooling morons that can’t even put food in their own mouths, with a single shot.
A later book, Pebble in the Sky, has Earth First terrorists developing and (attempting to) release a genetically-engineered plague that will kill all humans, except for those who have remained on Earth for generations. No actual planets would be destroyed, but the deaths of trillions of humans still has to count for something.
In the classic computer game Starflight, you could find a handful of “Black Egg” artifacts, which turn out to be planet-killer bombs. Use them on the right planets, and you could end up conquering most of the Galaxy.
And in Googling to double-check that last one, I discovered that, once again, Wikipedia has already spoiled all the fun.
TNG had a couple that I can recall - the Crystalline Entity, which would destroy all organic matter, and the Tox Oohtat, that thing from the episode where Picard goes to Risa and meets Vash. It was supposed to stop all reactions in a sun…or something.
In the Lost Fleet series I think is the ultimate planet killing weapons, since it’s aimed not at single planets but basically at every inhabited and built up human planet…it’s a ticking time bomb in the guise of being the greatest discovery humanity ever had (of course, it’s really a Trojan horse given to us secretly by hostile aliens).
Sort of a makeshift weapon, but Samatha Carter once used a stargate to blow up a sun.
In the movie Battle Beyond The Stars, the villains’ Stellar Converter would initiate a self-sustaning nuclear reaction in a planet, turning it incandescent. And as an example of not total destruction but “good enough”, Fred Saberhagen’s Berserkers are described as being able to turn a planet’s surface into “a lifeless cloud of dust and steam a hundred miles deep”.
The Hammer That Smashes Suns from Creatures of Light and Darkness is a favorite of mine for the name alone.
Doctor Device from Ender’s Game can disintegrate an object of any size in a chain reaction, including a planet.
Forge of God involved a large pair of matter & antimatter neutronium filaments being dropped into the Earth; when they met, boom went the Earth.
The Culture has plenty of way to destroy a planet. Compressed antimatter, nanoholes, gridfire…
The Bolo series has World Burners; one destroyed Earth.
In Fury Born has SLAMs; “Supra Light Accelerated Missiles” that are tipped with artificial black holes and can “rip a planet apart”.
In Aliens and Allies, a small planet is blown up with many very large nuclear weapons. Interestingly, the planet was uninhabited and the planet was only blown up to provide a world’s worth of shrapnel to destroy an enemy fleet that had been drawn in close.
Master of Orion II had Stellar Converters that blow right through a planet; I used to destroy planets just to watch the cinematic.
In the novel Rogue In Space, the first two-thirds of the story revolves around a plot to steal a device that can convert an entire planet into condensed matter.
In the Buck Godot graphic novel PSmIth, the MacGuffin was a device that would form a mini-black hole that would devour anything nearby- like any planet it happened to be sitting on.
Thermostellar Bomb #20 from Dark Star
Note, folks, that many examples cited don’t actually destroy the planet, they just kill all life, or all humans.
The Bionic Woman had a two-part episode called “Doomsday is Tomorrow” about a end of the world bomb that would go off if any country detonated a nuclear weapon. The weapon is only said to be capable of making Earth uninhabitable.
The Shawken Device, from a 1980s Star Wars comic, could theoretically destroy the entire universe. The inventor never got around to testing it, though.
Don’t know what weapon they used, but the Vogons did tear down Earth to make room for a hyperspace bypass. And if they wanted to be really nasty they could have broadcast their poetry.
In “A Taste of Armageddon” from ST:TOS season 1 Kirk and company threaten to blow up the warring planet, so it sounds like they have a planet buster aboard.
don’t know if this one actually destroyed the planet - the Vogons did.
I don’t know exactly what it’s called, but my cat has gathered together a bunch of odds and ends, old electronic and electric stuff, what have you. She gets awfully defensive about it if I approach it. She used to really like to watch Eureka on Sy. To be honest, it scares the shit out of me.
IIRC, at least in the dialogue that was actually aired, “General Order 24” simply meant that the surface of the planet would be devastated. Oddly enough, the novelizations of TOS claimed the Federation had “planet buster” bombs, but I don’t know if that was ever canon.
In the same vein of weaponizing a transportation device, doesn’t something really bad happen when (in the Babylon 5 universe) a ship opens up a jump point inside an already-open jump gate? As I recall, the stunt (1) picked up the name “bonehead maneuver” 
and (2) was used to keep scavengers from “desecrating” a recently-dead planet. :rolleyes:
It was primarily used to kill an “unkillable” (“no disrespect, but I’ve heard that before”) Shadow vessel. Sheridan just chose the particular gate he did because it’d stop the scavengers as a side effect, and he wouldn’t be ruining any live planet’s economy.
Sort of. If I remember correctly, what happened was that Sheridan destroyed the Markab jumpgate while getting away from a Shadow vessel. The planet wasn’t dead; the species that populated all died of a plague (Delenn and Lennier spent some time with them on B5 as they died); I think Sheridan was pleased because he got away from the Shadow vessel and because, without the jumpgate, anyone wanting to loot the planet would have to get there the slow way.
DAMNIT. Scooped.
OK, how about the cobalt bomb in Beneath the Planet of the Apes? The world didn’t come to pieces, but if I recall the end narrative correctly, it was left as pretty much a cinder.
From the Eekstravaganza episode “Eek Space 9”…
“According to my weird device, this is a White Dwarf Super Fusion Planet Popper Bomb. A terrible device capable of blowing up every planet in the known solar system like a batch of popcorn.”
The **Mycon **are a race of fungi-based aliens in the game Star Control II, and they populate themselves by sending their deep children into planets with cores and mantles like earth. After a few years, the deep children develop and explode all over the surface of the planet infected, and the entire world is completely destroyed, left only to be a charred, magma-covered and earthquake crazy shell of its former self.