You might hear other strange sounds that might go along with vibrations during vehicle operation. One that comes to mind is the operation of the ABS pump. This is a high-pressure pump that supplies pressure to the ABS system on some ABS systems. It might run for a few seconds at a time normally during vehicle operation. You mostly find this type of system on older vehicles. Newer systems use a different design that does not require the system to be constantly pressurized. For the most part, this is normal. However, if you have an ABS light on and you hear this noise, it could mean that you have an issue with the ABS system that should be looked into. This is one of the main ones I can think of at the moment, but there might be other noises or vibrations that occur normally during vehicle operation.
The main takeaway is that vibrations should be addressed sooner rather than later, as they could be an indication of a larger problem. Vibrations at speed are often caused by moving parts that are out of balance, not loose suspension parts or vehicle alignment. So if you have a vibration at speed, look to things that spin that might be out of balance. In fact, with just about all vibration issues, look to rotating assemblies for the cause. Once they hit a certain resonance, the vibration occurs, so be observant in your search for the cause. At what speed or RPM does the vibration happen? Does it coincide with a noise? Any clues you can find will help you determine the cause of a vibration. You might also want to read through the Noises article for more information on tracking down the source of your vibration problem.