Basic Trope: All alien planets resemble Earth to a lesser or greater degree.
Straight: The crew of an intergalactic spaceship, the Armada, lands on the planet Brrakh, which looks exactly like Earth.
Exaggerated: All planets, everywhere, look exactly like Earth, right down to every continent, every country, every street, house, or person; they are all identical.
Downplayed: Brrakh is fairly close to Earth in gravity, atmosphere and similar vegetation, but is otherwise different enough to cause problems for the explorers.
Justified: Planets are made inhabitable to humans through terraforming, or colonization of non-Earthlike planets is irrelevant or just not discussed.
Inverted: Aliens arrive on Earth to try to "terraform" it into something more like their planet.
Subverted: Although the planet is said to be "M Class" and looks similar to Earth, the crew that lands on it discovers the entire surface of the planet is covered in quicksand.
Double Subverted: The planet turns out not to be covered in quicksand as the crew thought, they just happened to land in a swamp.
Parodied: The characters complain about Brrakh "not being suitable for habitation", not because of poisonous atmosphere or bone-crushing gravity, but because of overpriced coffee shops and lack of parking space downtown.
Zig Zagged: The crew of the Armada land on Brrakh, which is remarkably Earth-like (water, oceans, soil, fossils, plants, animals) and is a pretty good place to set up a long-term colony. But the analogues of Earth fauna and flora are strange, in some ways very different from the Earth one, and are also inedible. There's a thinner atmosphere with different composition of atmospheric gases, higher/lower gravity and also a very unstable climate.
Averted: The crew of the Armada land on Brrakh, only to find that there is no oxygen, the gravity is ten times what they're used to, and the planet's surface is covered in an acid that burns through metal.
Enforced: "Our budget's low and we can't afford to have set design make us a planet, so...let's just shoot this outside."
Lampshaded: "Here we are, on an uncharted alien planet! ... That looks exactly like Earth."
Exploited: The "Armada" just pulls up to a planet and drops a landing crew on it, without even taking readings, because they know they don't have to.
Defied: The xenobiologist on the "Armada" takes great pains to demonstrate that, while this planet looks earthlike, the biochemical pathways used by the plant life are really quite unique.
Discussed: "You know what, you're lucky this planet is so much like Earth or you wouldn't be breathing right now!"
Conversed: "I don't think they hire very competent set designers for the sci-fi space shows. Every time they go to an alien planet, it looks like they just went out to their backyard."
Deconstructed: The entire series arc deals with the "Armada" attempting to determine why all the planets they encounter are Earthlike. The un-earthlike planets have been terraformed by powerful aliens from the distant past, with mysterious machines left on them to maintain Earthlike gravity, atmospheres, climate, possibly even species composition. Evidence can be found on many worlds that these ancient aliens routinely committed genocide while transforming planets.
Reconstructed: All planets are not actually Earthlike, but the crew of the ship is so diverse, including metal-based hot worlders, fat-in-methane based cold worlders, energy beings, AI's and the like, all wearing sophisticated e-suits, that pretty much any planet looks just like home to some member of the crew.
Played For Drama: A new alien Big Bad tried to take over Earth, but other planets nearby look so much like Earth, that he destroys the wrong planets, killing thousands in his wake.