I want to start off by sharing that there is no wrong way to homebrew a world or campaign. Some worlds and lands may be desolate and hostile, primarily inhabited by creatures and monsters that reflect their environment, others have flourished with the use of magic and/or technology and the population has prospered with the land.
That being said, when it comes to the makeup of your populous in general locations that are not specific to a race or species with an integral history and heritage, DM/GM’s have a wonderful array of people and cultures to use as inspiration for new content.
I also encourage game runners to allow your players to respectfully explore non-traditional avenues for character creation. Let them have a diffferent skin color, hair color, potentially a “non-playable” race or monster for another level of elevation. Embrace their ideas, but feel free to help them refine it so their choices don’t become game breaking.
Related: Creative Corner: World Building
While exploring your options for varied content in your game there is a fine line between honoring culture and appropriating it, so it is vital as a creator that if you plan on using elements from our world in your TTRPG you do your due diligence while researching these topics and cultures. Sourcing your material will also be imperative for developing your story and characters, so be sure to keep track of your research.
Since beginning our campaign, I have tried to present a blend of characters for my players to interact with, making sure to offer a variety of races, genders, ages, orientations, and classes, with some NPC’s featuring a variety of disabilities much like our real world. Sure it’s fun to meet a salty sea captain missing an eye or leg, but sometimes a tavern keep, receptionist, or store owner will have a birth defect or disability to help garnish an interest and give my players an opportunity to learn about the world they play in without having to encounter everything personally.
Related: World Building – Governments
As an example, there is a book shop investor that my players are convinced is the owner of the book store within the captial city (thanks to his insistance). He is a war veteran who is missing a leg and has a homemade prothestic leg that likes to lock up in wet and rainy weather. His name is Arty, and he loves to spread his knowledge and learn secrets of strangers that he keeps as a treat for himself to delight in. He quickly caught the eye of our Rogue while resting in his reading nook under the spiral staircase and has helped the party learn a thing or two, but what I hope they learn from him is that life is worth living and that they should strive to tell a good story with their actions.
One of the best parts about creating a homebrewed world or adventure is the ability to explore avenues that source books don’t cover or are just starting to publish content for. You can have anyone and anything in your world giving your adventuring party a chance to interact with the impossible. If you are going to play with no-limits or precidence I highly encourage you to explore ways to add diversity and inclusivity to your game.