Best Oil depends on various factors such as the type of vehicle, its age, driving conditions, and manufacturer recommendations. However, some widely recognized high-quality oils include:

1. Mobil 1 Synthetic Motor Oil.
2. Castrol Edge Synthetic Motor Oil.
3. Pennzoil Platinum Full Synthetic Motor Oil.
4. Valvoline Full Synthetic High Mileage Motor Oil.
5. Royal Purple High-Performance Synthetic Motor Oil.
6. Shell Rotella T6 Full Synthetic Diesel Engine Oil.