I remember people used say google drive had a download limit of 10TB per day. However I have the impression that they changed something because at least twice I exceeded the quota when I'm sure I didn't even download 3TB...
To the best of my knowledge:
API: maximum 1000 requests pr 100 seconds
But I rarely download many TB in a day, so I can't say I have tested this. In fact - I don't have enhough bandwidth to even try that
It may have changed I suppose - if so I have not heard about it though. If anyone has evidence that it did then I'd like to see it.