I think everyone should take some time in making more things to their liking. Look at a series you really enjoy, look at what you wish it had and how it could be better. Take that information and create what YOU'D like to see.
Want more non-white protagnonists? CREATE SOME ONE THAT'S INDONESIAN, HUNGARIAN, ICELANDIC, SOUTH AMERICAN, INDIGENOUS OR ARABIC (ANYTHING!!).Want more ladies? MAKE SOME BADASS AND CUTE GIRLS THEN. Can't stand all the hetero? MAKE SOME SEXUALLY DIVERSE BABS. Tired of all the cis characters? MAKE SOME NON BINARY SWEETHEARTS.
I've been SICK of seeing cis white hetero casts in every show/movie/book, etc so I told myself to make more non-white characters to satisfy that, even permanently race bend ocs of mine. And it's been very cool :D
Even if you're not the writer/artist type, collaborate with someone that is and create something together. Advertise your ideas! You can bring a difference into the mainstream, you just keep creating and making things BETTER. Don't sit there and complain all day about what ISN'T there, though it is fine to bring that to light (cause damn...). Actually make something you wanna see! We're in an age where things are changing for the better, you can create something so amazing and original, please try to bring your ideas to the world. Don't say you don't have ideas, if you're able to critique a game for not having enough females then you're able to give insight of what KIND of females you wanna fuckin see in mainstream stuff.
Your mind is a creative machine, you have the power to make something that is bound to catch someone's eye. I'm sure people will appreciate more diverse casts. Just cause we're not well known, doesn't mean we have no power in what we make. We're aware of how different people can be, so let's bring that to light and show the world that we as people are not all about hollywood glamoured cis hetero bullshit.
Let's bring more to the table that we consider the norm!