- Alien Landmass
Weird land, continents, or highlands which immediately show that the planet is not Earth.
- Alien Sea
The planet's sea has unusual features/appearance that visually sets it apart from the Earth that we know.
- Alien Sky
The sky looks very different from that of the Earth that we know.
- All Planets Are Earth-Like
All alien planets resemble Earth to a lesser or greater degree.
- Baby Planet
An inhabitable planet that is far smaller than astronomically possible, often less than a few miles in diameter.
- Binary Suns
This planet has more than one sun in its sky.
- Casual Interplanetary Travel
Interplanetary travel is quick and inexpensive.
- City Planet (aka Ecumenopolis)
A planet covered entirely in city.
- Conveniently Close Planet
Traveling from planet to planet is much easier in fiction than reality.
- Death World
This planet is so dangerous that simply going there is considered taking your life into your own hands.
- Earth-Shattering Kaboom (aka Planetary Destruction)
When The End of the World as We Know It entails the destruction of the entire planet you're on (not necessarily Earth, despite the name).
- Genesis Effect
The birth of a planet, through natural or artificial means, usually with a good deal of impressive visuals.
- Ghost Planet
What you get when a Ghost Town is global in scale.
- Homeworld Evacuation
A planet has been struck with a disaster that forced (a portion of) the native population to leave for outer space.
- Interplanetary Voyage
A story where space travel is less concerned with the destination and much more with the journey itself. Common in early Science Fiction, not so much in modern times.
- It's a Small World, After All
Planet equals small town.
- Landfill Beyond the Stars
An entire planet is used as an interstellar municipal landfill.
- A Long Time Ago, in a Galaxy Far, Far Away...
A story is set on a planet in a galaxy so far, far away that the very distance lends an air of credibility to even the most fantastic of plots.
- Metal-Poor Planet
A planet is lacking in metals or metal ores, which causes problems for the people living there.
- Multicultural Alien Planet
This world is no Planet of Hats; its native population comprises several distinct ethnicities and cultures, each with its own traditions.
- Named After Their Planet
The name of an alien race is derived from the name of their home planet. Conversely, aliens will tend to call humans by a name derived from Earth's own, such as "Earthlings" or "Terrans".
- Naming Your Colony World
Naming Conventions for colonized worlds.
- New Eden
An exiled race discovers that their once ravaged homeworld has healed over.
- Numbered Homeworld
An inhabited planet lacks a proper name, instead is known by the name of the star it orbits and a number.
- Paradise Planet
A beautiful, hospitable world portrayed as a wonderful place to visit and the perfect place to live.
- Pastoral Science Fiction
A green, fertile agrarian planet.
- Planet Baron
Somebody who controls and owns an entire planet.
- Planet Eater
A character that not only destroys planets, but eats them for nourishment.
- Planet Looters
A species or group has run out of a resource on their own planet and now must steal it from others (usually Earth).
- A Planet Named Zok
Just as aliens can have bizarre names, so goes for the names of alien planets and other celestial bodies.
- Planet of Hats
An entire world/species is culturally uniform with a single set of quirks shared by all of its members.
- One-Product Planet
A planet that specializes in providing a single commodity or service on the interstellar market.
- Planet of Copyhats
An entire race's "hat" is extrapolated from the behavior of one or two characters.
- One-Product Planet
- Planetary Core Manipulation
Draining, poisoning, destroying, or stabilizing the core of a planet.
- Planetary Nation
An entire planet is ruled by a single government.
- Planetary Parasite
A parasite that victimizes planets instead of the organisms living on them.
- Planetary Relocation
Relocating a planet.
- Planetary Romance
Stories, nominally Science Fiction, set on alien worlds described in lush detail. The world can be Earth in the far distant future, or an alien planet, but it is reached by science-fictional means, not magic.
In Space Opera, entire planets serve the same function in space that towns and countries do in more traditional planet-bound stories.
- Pleasure Planet
An entire planet that is dedicated to providing luxury and pleasure to its inhabitants/visitors.
- Rogue Planet
A planet that wanders in interstellar space outside of a solar system.
- Sacrificial Planet
The plot-driving threat destroys a less important planet first.
- Shattered World
Once a planet, now broken into small pieces floating through space.
- Single-Biome Planet
This planet has no ecological diversity: it's dominated by a single environment type, often regardless of latitude.
- Single Language Planet
All inhabitants of the planet speak the exact same language, no exceptions.
- Strolling on Jupiter
Planets known not to have solid surfaces, such as gas giants and ice giants, are depicted as having traversable land masses.
A planet's enviroment is artificially changed to better suit a species, human-like or otherwise note .
- Hostile Terraforming
Making a planet less suitable for native life and more suitable for alien life.
- Hostile Terraforming
- Tidally Locked Planet
A planet is tidally locked to its star the way the moon is to Earth; one side is always day, one side is always night. Extreme opposing temperatures (burning hot on the day side, bitterly cold on the night side) often result from this.
- World Shapes
Speculative Fiction is rife with unusual choices for a planet's shape, as a way to drive home the exoticness of said planet in comparison to the more familiar Earth.
Tropes about the Solar System's planets
- Colonized Solar System
Humanity has several space colonies across the the Solar System.
- Industrialized Mercury
The closest planet to the Sun is used as a hub for industry, mining, and/or energy production for Earth or the whole Solar System.
- Once-Green Mars
Depictions of Mars as having once been bountiful and full of life, perhaps even home to a thriving civilization, before some disaster left it as the lifeless red world we all know today.
- Pluto Is Expendable
Pluto treated as the Butt-Monkey of the Solar System.
- Solar System Neighbors
When bodies in the solar system are inhabited.
- This Index Earth
An index for all tropes specifically about the very planet that we humans live on.
- Uranus Is Showing
Making a joke about Uranus and its name's unfortunate homophony to a certain phrase.
- Venus Is Wet
Venus is permanently covered by clouds; that surely means that they're concealing a thriving biosphere with tropical rainforests and/or vast oceans!