Random Rotate XYZ is an add-on which allows you to rotate randomly in all 3 axis.

Alt+Q is the hotkey

It have 2 modes - Increment & Normal

Increment will let you rotate in random increments of the specified axis.

For the Normal Random Rotation, you can specify a minimum and maximum value for each axis

For all the angle inputs, values can range from -360 to 360

You can choose between Global, Local and Custom Orientation, for the rotation axis

What is the Custom Orientation?

It allows you to choose a custom object to determine the initial orientation/rotation of all the selected objects.

All the profit goes to Blender Dev Fund

If you find any bugs or would like to contribute to the code, here's the GitHub Page

Watch in-depth guide on YouTube