The first one is the trolls. In Raymond Fiest's 'Magician', they are described as "human-like, but with large arms and a thick ape-like skull with fangs. They had mottled fur, and a peculiar third eye atop their head." http://images.wikia.com/elderscrolls/images/2/23/Troll.jpg
Then there is also 'Guild of Thieves' which, in both 'Magician' and 'Siverthorn', act in the city of Krondor. Here's some traits they have which are clearly described in his work.
"The people of the Poor Quarter look up to us. We keep the guards... away, and do not impose tax. What do we get out of this? (there's always something) Eyes and ears amongst the citizens." - Jimmy.
The Upright Man is basically our Guild Master, for lack of another word. He is never seen, never heard. It's like he doesn't exist. Even I haven't seen him." - Jimmy.
"The Upright Man loves a little glory. That bastard Guy Du Bas Tyra hasn't let us have our run of the place for months. A little excitement along the way is always nice, too." - Crook.
The Upright Man is basically our Guild Master, for lack of another word. He is never seen, never heard. It's like he doesn't exist. Even I haven't seen him." - Jimmy.
"The Upright Man loves a little glory. That bastard Guy Du Bas Tyra hasn't let us have our run of the place for months. A little excitement along the way is always nice, too." - Crook.
I think this one's nitpicking, but Thieves Guild and The Gray Fox, anyone...?
Then there is the Moredhel, the Brotherhood of the Dark Path. These people are basically Elves who left the Elven land of Elvandar and turned to darker ways. They are described as having Dark grey-brown/blue skin and their eyes are either red or brown. They are also despised by the 'Pure Elves' of Elvandar.
Again, I may be nitpicking, but I saw the (correct me if I'm wrong) the exodus of Elves from Summerset, who then became the Dark Elves. And also how the 'purest and rightest' Elves hate these Elves.
Now, I'm not talking down on TES at all here, everyone gets inspiration from someone. I think it's nice that I, as a fan of Raymond E. Fiest's work has been of influence, allowing me to see some of his ideas in a more real way.