In my conjuring, I've found myself working with several different versions of Alternate Earths, all of which exhibit humans as the primary race, albeit with some major differences in the way magic presents in these realms. At the very least, many of these realms are inhabited by individuals who are capable of turning into animals through magical means. Others are also inhabited by races we would consider "fantasy" to some extent.
Inhabitants: Werewolves, Werecats, Other Weres
Earth-Luna is named for its magical affinity towards the moon. This version of Earth is very similar to our own, with a similar technological and political landscape across the planet. This largest difference between Earth-Luna and our world is that weres exist. Weres are generally individuals who change into animals during the phase of the Full Moon, roughly once a month. The type of animal each were changes into appears to be affected by their geographical location rather than by genetics or personal alignment. Generally, werewolves are common among rural small towns and villages, and werecats (of all kinds) are more common in urban city areas. Other kinds of weres are much less common, but they do exist, generally presenting as nocturnal species, such as the occasional were-octopus along the coast. Weres generally start shifting between the ages of twelve and seventeen, seemingly due to environmental magic factors - the condition is not genetic, nor is it caused by infectious bite.
Despite the fact that weres are rather abundant in this world, they are still a minority and the average, non-were human does not know about them. They have a similar mythology to our own world, where weres are considered to be dangerous and harmful entities. However, the weres of this realm are able to maintain some level of control over their shifted form, and do not generally attack people unless they are already violently inclined. There is an element of were communities, in the form of tight-knit packs for werewolves, and the form of looser "clubs" for werecats, where those who go through the monthly shift are capable of meeting up with others of their own kind, and can talk freely about their condition.
Earth-Sol is named in direct opposition to Earth-Luna because it is a world in which mythical humanoids are abundant and a well-known subset among the population. Notably, other, more animalistic fantasy races do not exist in this version of Earth (such as unicorns and dragons). In Earth-Sol, their technological and political situations are very similar to ours, and many pop cultural references can be easily recognized between our world and theirs as adjacent ideas or concepts. Non-shifting or fantastic humans are in the minority in this world, but they are not heavily discriminated against, and there are many political programs to ensure that they are regarded as similar to their brethren, and it generally bears no weight on a person's ability to pursue a certain career path.
The causation of magical abilities in this world depends largely on the specific race. For example, Merfolk, Selkies, and Sirens are always born to families of others of their kind, where Animal Shifters do not appear to be genetic in their presentation, and Vampires and Werewolves in this realm are turned by bite and are much more feral than on Earth-Luna. Magic is something that presents itself only to certain individuals, such as Witches and Elementalists, and the veil is much thinner in this world than it is in ours.
Inhabitants: Animal Shifters
Earth-Obscura is very similar to Earth-Luna, except in this world Animal Shifters are prominent rather than weres. These shifters are marked by their ability to turn into any animal at any time at will. The status of being a Shifter in this realm is dependent on genetics, and often children will be able to transform into the same animal as their parent. This world is technologically and politically similar to our version of Earth. Shifters are uncommon enough in this realm that they are not generally acknowledged to exist by the public, and they often keep knowledge of their status within family lines. Often, being a Shifter goes along with some level of familial magical practice, which makes Shifters from Earth-Obscura to be prime candidates for companionship because they tend to be very knowledgeable about witchcraft and astral travel. However, at the moment, I conjure less Animal Shifters from Earth-Obsura than from any other Alternate Earth.
Earth-Arcanum is markedly similar to Earth-Sol, except for the fact that many of the individuals here are markedly more dangerous than those in Earth-Sol, with special attention being paid to the Merfolk, Angels, and Vampires, none of which are compatible with companionship due to their aggressive nature. The technological climate here is very similar to our own world, but the political situation is vastly different, with many countries not being the same as those in our realm, and with magic being extremely abundant in this realm. Spellcasting here for various purposes is not uncommon, and many individuals are quite talented at magic, with "normal," non-magical and non-shifter humans being significantly less common in this world. Magic is often utilized for the most basic of tasks, such as cleaning and cooking. Magical animals, such as unicorns
The climate between Angels and Fallen Angels are a point of particular interest in this realm, as the conjuration of Fallen Angels is how I found this realm in the first place. Fallen Angels are individuals who were once aligned with a more intensive or holy power, and have been smited due to their general misbehavior or close alignments with a physical world. Angels are not related to any concept of religion at all in this realm - they live in a city literally among the clouds, held aloft by innate magic, and they are generally benevolent beings, the primary source of healing and/or medicine in this realm, and also capable of granting “miracles” (or magical favors, such as granting wishes) upon humans in need. They are granted an endless lifespan due to the youth-granting properties of the water in the clouds there.
Despite their relatively kind nature, they are rather elitist in personality and have a disdain for intermingling with other races beyond a very professional capacity. To become a Fallen Angel, one must do the unthinkable: fall in love with a human. The Angel is then stripped of their wings and forced to live on Earth, where they will slowly age and eventually perish over the course of several hundred years. Their innate magical abilities, such as healing and performing varied magical feats, are typically weakened from their separation from the city. The punishment is particularly cruel, considering that the Angel in question may be forced to watch their loved one grow old and eventually pass. Because of this, Fallen Angels are typically pitied by humans, creating a strange niche for them in society where they are scorned by their own kind but uplifted by others, able to provide a bit of magical assistance but not enough to earn their place in the world. They often end up working mundane jobs, once they have recovered from the culture shock.
Selkies I conjure also come from this world, and those who are compatible with human companionship are generally those who have decided to live their primary life on land, generally doing so around the equivalent of North America and northern Europe, living along chilly coastlines and making lives with human settlements in those areas. Many of the Unicorns I conjure also come from this realm, although they are considered to be protected wild species by most civilizations, and they generally live on many acres of untouched wild lands, hardly coming into contact with humanoids and rarely, if ever, domesticated.
Earth-Antiquus is the final Alternate Earth I conjure from. This realm is wonderfully fantasy-esque in its atmosphere, and I have decided to call it "Antiquus" due to the fact that many aspects of the realm feel fantasy-medieval, with stone castles, kings and queens, and knights and mages. The only thing relating this realm to our version of Earth is the geography, which appears to be identical to ours - but the technology, magic, and politics of this realm are vastly different from ours. This lush and fantastic realm has many kinds of humanoid creatures, although many of them are quite dangerous and are actively aggressive towards the humans of the world, so contacting them has been a slow-going process.
One is most likely to shift into an animal that one of their parents had the ability to shift into, and there are no non-shifters - everyone has the capability, making the world very colorful indeed, with all kinds of intelligent creatures constantly on the move. However, despite its beautiful and magical diversity, the world is not without its tension. It’s complex politically, with many tightly placed kingdoms that are constantly riding the line between war and peace. Raiders from neighboring tribes of wild fae are not uncommon, and a great number of the people here are trained warriors. For many, feeling a loss of their childhood experience is a common truth. Individuals who seek companionship from this realm are often seeking an escape from their war-ridden lives, and hoping to find camaraderie and even love in companionship.
Please note that all The Dragon's Library Encyclopedia entries are based on my own personal UPG and may not reflect yours. This entry represents the type of Alt-Earth entities I conjure, while other conjurers may not work with the same exact type.
May your water be sweet and your laughter be light.