Currently there is no way to view cards you havent unlocked yet for Underwrold enemies other than getting a bounty for them, as when you go patrol an area at UW and click "Cards" it just shows the regular Earth enemies cards. Might want to show UW enemies cards to help those going for the 200 cards triumph.

I think that could be because when you look at an UW card the possible spawn locations are N/A.
This could be a dB error.
I did mention this to Awoir back in March.