I finally found the source file for that. I posted a screenshot of my phone months ago and people were asking for it, but I had no idea where it was. A little late, but I guess I finally delivered lol.
I made a live wallpaper using an Android app called Magic Fluids (https://play.google.com/store/apps/details?id=com.magicfluids) that is fully black, but creates a flame effect every time I tap the screen or slide my finger across it. Yeah, edgy and tacky AF, but it really is a pretty cool effect and I've been using it for years, so whatever.
I believe it was just a one-time purchase for the full version of the app. The animations don't loop very well, but I'm not staring at my home screen long enough to see the loop that often, so it's not a big concern to me. They're pretty much all swirly, inky, starry sort of abstract animations, but there's a lot of color options so it's pretty easy to pick something that fits well with the rest of your phone's theme.
The developer hasn't updated it for over a year now, so if the previews don't look like something you'd like, I wouldn't bother buying the full version since it's unlikely that any more will be added.