I was thinking: instead of using atmospheric noise for entropy, one could use a variety of different things taken directly from the user, like mouse movements (

I was thinking: instead of using atmospheric noise for entropy, one could use a variety of different things taken directly from the user, like mouse movements (Veracrypt uses the mouse to seed random values for example). You could even use things like the user's timezone, HTML5 Canvas fingerprint, even the order/arrangement of icons on the desktop. There's so many sources!