8-Demon Slayer
may be relatively new, but that doesn't mean that it can't still be included in conversations surrounding the best anime series of all time. After all, it's been able to generate around $10 billion in revenue in the six years or so since its creation, which is around the same as more established media franchises such as Thomas the Tank Engine and Sesame Street; both of which have been around for well over half a century.
Death Note
MyAnimeList Score: 8.62
Light Yahami holding Death Note
Similar to the likes of Sword Art Online and the Fate series, Death Note is seen as something of a gateway anime. As a result, some seasoned anime fans seem to enjoy going out of their way to pick holes in its plot and pointing out all of the shows that are supposedly better than it. However, there's a very good reason why so many people are advised to try Death Note when first dipping their toes into the vast anime waters.