Here we look at Jeev Milkha Singh.
From the Face On view the swing looks somewhat orthodox.
From the DTL view is where we see some oddities in his swing.
He has a pretty upright address position with little flex in his knees. He then takes the club a little outside and laid off at P4, but the really lowers his Center of Gravity (COG) and gets the club on the elbow plane beautifully.
Then at impact he has 'plenty of right arm' and saves that right arm past impact.
I think that a key to Singh's swing is he keeps the right heel pretty flat on the ground at impact. While it's hardly mandatory, it helps Singh lower his COG which is needed given how high his COG at the top of the swing.