So I love creature shields and posed these questions to myself a while ago. After much boring research its clear that nothing in fow/uw drops anything other than vs undead mods (including weapons). Is my opinion that Topk can drop Eternal and gloom with Giant, Charr, Tengu, Troll, Undead, Skele, Dwarves & Plants.
I dropped this myself a few months ago and have seen many non undead mods on weapons / shields:
Have confirmed all but dwarves as a possible mod on topk items but fair to presume its possible.
There is also these. Either also dropped from TopK or were from UW and creatures other than undead are prenerf. I think the former is more likely after speaking with people who have better memories than me on the subject. (The q8 obviously being prenerf regardless)
There is also these to explain. Clearly very old very prenerf, I've come to the conclusion they are from keyless chest in fow all those years ago and I also believe that the full list of proph creature mods was possible. (Giant, Charr, Tengu, Troll, Undead, Skele, Dwarves & Plants)
If anybody can confirm or deny any of this please do, keen to figure out the truth of it all