For example the computer's fan motor.
If you think about it a BLDC without sensors is just a "three" phase synchronous motor, or maybe even a low pole count stepper motor, so yes you can drive it without sensors.
With sensors of course you can maximize the torque and control the phase angle to a high degree of precision and reduce the power consumed by the motor. Further, with sensors the motor can also drive much more variable loads without stalling.
As Neil suggests there are also ways to use the back-EMF from the motor to control it without sensors too that give you a less precise compromise.
Hall sensors are necessary if you want a BLDC to start with high torque, or be controlled down to very low speed.
If you simply want a spinning motor for a propeller, then the ESC can work with the back EMFs from the coils themselves to control current and speed, after a few trial pulses have kicked it into motion. This is the so called sensorless mode of control.