The C21 range contained both Goblin and Undead Cavalry. They were all single piece castings. Some of them were recoded Fiend Factory pieces, others new sculpts. In the US two of them were released in the FTS, and one in the Fiend Factory ranges.
C21 Undead Riders
C21 Skeletal Fanatic
FF66 Skeleton Rider on Horse of Hell
C21 Skeletal Knight
C21 Grim Reaper on Hell Horse
C21 Wraith Rider
FF3-2 Wraith Rider on Undead Horse
C21 Undead King
C21 Plague Rider
C21 Wraith Rider