Every character who appears in the HP series in person
+ those who appear in chocolate frog cards
+ those referenced to by other characters
+ Magical Creatures/pets.
+ Authors of textbooks/magical books
+ Ghosts
- International Quidditch players from Quidditch through the ages are excluded (but those mentioned in GOF are not)
Good quiz - may I suggest these additions: Wilbert Slinkhard, Miss Fawcett, Mr Summers, Gamp (as in Gamp's Law), Golpalott (as in Golpalott's Third Law), Dr Ubbly (famed for his Oblivious Unction), Cadwallader (the Hufflepuff Quidditch player in Half-Blood) and the Montgomery sisters (first names unknown.)