It would be really useful in Assemblies, if you could press and hold Shift to snap to 90 degree positions when rotating a component with Free Rotate. I.e. when you click and drag on the outside of the circle below.
This is something that other applications do, for example MS Office and Adobe products. If you do not press the shift button it could do the same behaviour where it rotates to any angle. But then as soon as you hold Shift whilst rotating it snaps to 90 degree position.