The extreme cases of Imperials are very racist, but they seem too be less racist than the Altmer and Dunmer on an average basis.
Breton Trash
Goldenrod
You elves are all the same! All flash and no fury!
Pondscum
You make a fine pair of boots, lizard!
Treehugger
Ashborn(even if they embrace the identity)
Imperial dog
Furlicker
Mangy housecat
Snowman
Dungheap
Come to bother me with a war story, Redguard?
Edit: One point per correct that does not have the race named in it