| 🚰 Drain System |
| 💧 Dry System |
| 🌿 Duckweed System |
| 🌪️ Dust System |
| 🌌 Dusty System |
| 🧠 Emotional System |
| 💧🛢️ Emulsion System |
| 🗑️🧠 Erasitory System |
| 🌍 Eurasian System |
| 💻🤩 Fan System |
| 🎨 Fanart System |
| 📚 Fanfiction System |
| 🚜 Farm System |
| 🌾 Farming System |
| 💻🚫🤝🚫 Fascist System |
| 🏰 Feudal System |