Let's start with the minor offenders and work up to the really bad ones.
First off, Planet Vegeta:
[spoiler]

A terrestrial planet with 10 times Earth's gravity is quite implausible in real life, but as its size is never stated this is hardly the craziest thing out there. This one isn't so bad.
North Kaio's planet:
[spoiler]

Same gravity as planet Vegeta, but roughly the size of a hill. The density of this thing would be comparable to a white dwarf star, except those are at least the size of the Earth. Still, the density isn't impossible going by real physics, and it's a planet in the Other World so more leeway can be given. Still significantly more implausible than planet Vegeta.
Comet Camori:
[spoiler]

A 'comet' large enough to completely destroy an entire planet. Even hours from impact it is so large it fills up a huge portion of the sky. Obviously no comet in real life can be this large. If anything, it should be called a rogue planet. But if you ignore the 'comet' designation and assume that it's not actually a comet, it's not so bad.
Beerus' Planet:
[spoiler]

If you assume that this thing actually is a planet, then there are tons of problems. Not only is the size ridiculously small, but the shape is obviously wrong. Anything close to the mass of a planet would be pulled into a sphere by its own gravity. This place has Earth standard gravity, but unlike North Kaio's planet the gravity isn't oriented around the center of its mass - it has a clear top and bottom. Even inside of it, the gravity pulls you 'down', not towards the center.
If we don't consider this an actual planet and more of a temple then it makes much more sense, although are still the problems of the many 'moons' orbiting around it. It makes little sense for bodies so small to be such perfect spheres, and if they orbit the temple then it must have strong gravity, but the problems with the gravity were already mentioned. This one doesn't make much sense but, like North Kaio's planet, it is an Other World/godly/supernatural place, so it gets a bit more wiggle room.
Zuno's Planet:
[spoiler]

This one is inexcusable. It's not in Other World or some magical place, it exists in the normal universe, yet it has the same problems with the shape and gravity as Beerus' planet. The only real way to make sense of this is to assume that it is an artificial construct, not a real planet.
And this brings me to what prompted me to make this topic in the first place, the Prison Planet:
[spoiler]

Even someone with zero knowledge of astrophysics can easily tell that this thing is ludicrous. But the more you know, the more ludicrous it becomes. I could spend all day listing off the problems here. Literally the only justification for the existence of this thing is that it looks cool (although to me, it looks more silly than cool).
I just wonder how they're eventually going to top this in terms of scientifically impossible planets.