As the title says, I've found a list that claims to feature all languages in the world. A big claim, but with 7861 entries, I imagine it comes close. It should provide a lot of use for writers who work with the real world, or those of us (me included) who simply like scrolling through them and learning a bit. The link can be found here: https://www.101languages.net/list-of-all-world-languages/