Animation is sometimes referred to as a genre, but doing so can be contentious, given works of animation are able to belong to any genre live-action works do, and "live-action" doesn't tend to be considered a genre. When approaching animation as a format, it thereby becomes far less surprising that animated works can deliver just as much as non-animated works, with this being applicable in both the world of cinema and television.
To focus on the latter, the following episodes of television all demonstrate how great animated TV can be, and all rank up among the best of all time when it comes to this format. To keep things interesting and a little more exciting, there's a limit of one episode per show, with each show/episode ranked below from great to greatest.