The "normal" leaky places might be the valve cover, maybe the oil pan gasket, harmonic balancer seal. These are slow leakers (but could get worse.) We're talking gravity leaks or slung out of an opening.
As far as "sudden and heavy loss" parts, one might look at the oil pressure sending unit. These items are generally metal and screw into the engine. The "kicker" is the center portion of the sender is plastic. The unit is under constant oil pressure. So when the plastic portion separates/cracks loose on the sender, you have a 30-70 PSI stream (just a wild guess) of oil constantly leaking out. It doesn't take long to expend a bunch of oil.
This is a guide from our "Repair Guides" (top right of our pages) It might aid with some of your leaks.
Not saying this is the issue, but something to check out, below are a picture of the oil sender, the other being it's location.
Images (Click to enlarge)
Saturday, February 2nd, 2019 AT 5:50 PM