hi! a similar question came up the other day which you may be interested in

• Has our modern-day portrayal of goblins, elves, giants, gnomes, etc. changed much from their original legends?

... and there have a been a few other related posts you might get something out of

• When did "faerie" become benign-magical and not scary-magical? What did "faerie" mythology entail in the pre-modern era?

• How did the Norse treat people with dwarfism? - contrary to the title, this thread is largely an unstructured discussion on various definitions of "dwarf" and various other beings

• Were there cases of families treating their children badly because they feared their child was a fey, troll or changeling? (If I need to be more specific, then Scandinavia.)

• What parts of Tolkien lore were invented by him and what parts were drawn from an already established mythical history?

• Why didn't elves survive the transatlantic crossing?

• When and how did elves become a part of Santa Clause's lore?

Quick note: Orcs are creations of J.R.R. Tolkien, not a part of the English folklore. More specifically the name 'Orc'. The other name for orcs is goblins. (Orc is elvish)