Houseki no Kuni, Hataraku Saibou Recommendations
Both are set in a world that feels very alien to the viewer, lives by strict rules and is under constant attack of alien entities (lunarians in Houseki no Kuni and bacteria in Hataraku Saibou). Both have a large cast of human-like, but not actually human characters, with different episodes focusing on different ones, and protagonists (Phos in Houseki no Kuni and Red Blood Cell in Hataraku Saibou) who are pretty incompetent and strive to become better at their job.
Land of the Lustrous and Cells at Work! are both adaptations of manga from a monthly magazine published by Kodansha. The characters in both series are humanoid versions of non-human things, cells in Cells at Work! and gems in Land of the Lustrous. Everyone in each society has a specific role that they are best at and must do. The society in each anime must fight of an invading species, Lunarians in Land of the Lustrous and Bacteria in Cells at Work!. The main character in both series aren't good at their job at first, but slowly improve over the show.