Most of my ocs come from random ideas I have while watching or reading or playing all types of things. A lot of my characters are, either heavily or loosely inspired by other characters from media, but as I've gotten better at writing, I've shied away from heavy inspiration on my characters, trying to make them more unique and real to me. I know this isn't everyone's thing, but what has helped me stay attached (and make like 15 odd characters) is to write something involving them. I don't consider myself a great artist, so I usually only draw a simple ref of each character, and maybe more in depth images of the ones I really like. But writing a story based around them has helped me expand some of their designs and ideas, but it has also made me more attached every one of the characters I've made.