Just like in the comics, the DC Extended Universe features characters from various species, several of which have been explored in the franchise. While several of those races originate on Earth, others come from distant planets and dimensions with the majority of them possessing superhuman abilities.
Although they've only scratched the surface of the different races that exist and there are still plenty that they could introduce in the future, there are plenty of differences in the ones they have shown that make all of them unique, especially when it comes to power levels.
Humans
Humans are the primary species of Earth that was created by Zeus over 200 millennia ago in the image of the Old Gods and later corrupted by his son, Ares, who influenced them to go to war with each other. They fought alongside the Amazons and the Atlanteans in defending Earth from Steppenwolf during the first attempted invasion of the planet. While they don't have any special powers, they can be incredibly smart and have made great advancements in technology that have allowed them to develop rapidly over time.
Parademons
Parademons are winged creatures with glowing red eyes, sharp fangs, and claws that serve as the members of the army of Apokolips. They are shown to be created after coming in contact with the energy from Steppenwolf's weapon. Any species is capable of being transformed into one and after they do, they basically become mindless drones with no other purpose other than to do the bidding of their masters. Their bodies are also often covered in armor and they often wield Apokoliptian weapons, usually in the form of guns. They aren't particularly strong seeing as Batman was able to take them on with little effort but what they lack in physical strength, they make up for in numbers. They can also sense and feed off of fear which led them to turn on Steppenwolf after he was defeated by the Justice League.
Metahumans
Metahumans are a subspecies of humanity made up of individuals that have demonstrated unique superhuman abilities, either on account of genetics or experiments. The term was created by the character Lex Luthor after collecting information on those who would go on to become members of the Justice League although it technically only applied to the Flash. While some of them can still look human such as Barry Allen and El Diablo, others may have altered appearances like Cheetah and Killer Croc. Their powers and abilities can vary greatly to the point where almost no two metahumans' powers are exactly alike, even if they might be similar.
Amazons
The Amazons are a race of all-female warriors that were created by Zeus, led by Queen Hippolyta, and reside on the hidden island of Themyscira which is located in the Mediterranean Sea. Although they were created to safeguard the world of man from Ares and his control, they eventually isolated themselves until Diana ventured out to aid mankind.
All of the Amazons are trained from a young age to be excellent fighters and have enhanced strength, coordination, stamina, and agility. They are also blessed with the ability to speak all human languages and while they are immortal and have no specific weaknesses, they can still be killed.
Atlanteans
In 3000 BC, Atlanteans were the most technologically advanced civilization on Earth that lived in a city called Atlantis and were led by King Atlan. However, after the "Great Fall," the city sank to the bottom of the ocean and broke off into seven kingdoms, each with its own distinct culture and rulers and only four of which have survived. Due to the city being underwater, its people evolved in various ways. While Xebelians like Mera and Atlanteans like Orm and Vulko look similar to humans, the other subspecies do not. The Fisherman have tails, gills, and scales like fish, the Brine resemble crustaceans, and the Trench are blind creatures with sharp teeth that have a fear of light as a result of them living 2500 meters below sea level.
Homo Magi
Homo Magi are characters that are capable of magical manipulation. So far, there have only been 3 characters that fall into this classification: Enchantress, her brother, Incubus, and the wizard, Shazam. It is unclear how these beings came into existence or how they acquired their magical abilities but they were also all worshipped by previous civilizations as gods due to their abilities which vary from each other. They are individually capable of things like possession, telekinesis, and teleportation but one ability they all seem to share is immortality seeing as all of them came into being before 3000 B.C.
Kryptonians
Kryptonians are aliens that originate from the planet Krypton which was destroyed due to mining of its core which resulted in an implosion. While Kryptonians don't possess any powers while on their home planet due to it being in the orbit of red star, the radiation from Earth's yellow sun grants them superhuman abilities like flight, enhanced strength, speed, and durability.
Their senses are also increased giving them superhuman hearing, breath, and sight which includes laser vision, x-ray vision, and Microvision. They can, however, be weakened by a mineral called Kryptonite which can make them as weak as humans. Currently, Kal-El who is also known as Superman by the people of Earth is the last surviving member of the race.
New Gods
New Gods are an alien race that come from one of two homeworlds, New Genesis, led by Highfather, and Apokolips, led by Darkseid, which have been in an ongoing war with each other. They are some of the strongest beings in the universe but are still weaker than Krptonains and Olympians, which is why they failed their first attack on Earth and why they waited until Superman was dead on Earth before launching a second one. Based on Steppenwolf and Darkseid, they are incredibly strong and are basically immortal. They are the inventors of the Mother Boxes which can open portals for interdimensional travel called "Boom Tubes." While not much has been shown about the New Gods of New Genesis, it's expected that they'll be properly introduced in New Gods directed by Ava DuVernay.
Olympians
The Old Gods, also known as the Olympians, are beings from Earth like Zeus, Ares, Poseidon that were worshipped by ancient humans as deities but, over time, became known as myths. While they may look similar, Old Gods are much larger than that of the average human. They are more powerful than both New Gods and Kryptonians as they can only be killed by other gods or demigods. They were almost all killed by Ares aside from Zeus who temporarily weakened his son and died after using the last of his power to create Themyscira. Ares was the last member of the race before his death at the hands of Wonder Woman.