Wheel lug nuts tightened in cross? If not it may shake.
Ball joints? CV-joints? Tie rods? Balance rods? Rubber bushes of all these things.
Also, all machine have a critical speed at which all loads try to go off at a tangent. Even the best machines. So this is the critical range of your car. Just pass this range quickly.
You can spend as much on these small annoyances. Waste of time and effort and money. The problem is not dangerous if every component is ok on inspection. Just live with it, otherwise the car will consume a fortune.