Drop object to ground or cursor

There should be a button on the left side screen, that (after pressing) drops any currently active object to either the ground plane (if no other object is blow the active object - only the grid and endless depth); or the current height of the cursor; or an object's surface, if it is beneath the active object. Like if you let an object fall to the ground in Real life. That way one doesn't have to care, for example, if a rig is exactly on the ground plane. Just press drop to ground. Done. Or if you wanna place an object on a table... and so on.