Below is a list of of what each category is organized: HintAnswer (image), then category/group:

Ron Weasley, Neville Longbottom, Seamus Finnigan, Dean Thomas – Harry Potter – Members of Harry’s Dorm

Miranda Goshawk, Bathilda Bagshot, Adalbert Waffling, Emeric Switch, Phyllida Spore, Arsenius Jigger, Quentin Trimble – Newt Scamander – First Year Set Book Authors

Arithmancy, Study of Ancient Runes, Care of Magical Creatures, Muggle Studies – Divination – Elective Subjects

Petunia Durlsey, Vernon Dursley, Harry Potter, Dudley Dursley, Piers Polkiss – Arabella Doreen Figg – Little Whinging Residents

Moony, Prongs, Wormtail – Padfoot -Marauders

Kendra, Aberforth, Albus, Percival – Ariana -Members of the Dumbledore Family

Rufus Scrimgeour, Pius Thicknesse, Cornelius Fudge – Kingsley Shacklebolt -Ministers for Magic

Remus Lupin, Dolores Umbridge, Gilderoy Lockhart, Alastor Moody, Severus Snape – Quirinus Quirrell -DADA Professors

Fleur Delacour, Harry Potter, Cedric Diggory – Viktor Krum -Tri-Wizard Champions

Chinese Fireball, Hungarian Horntail, Common Welsh Green, Swedish Short-Snout, Ukrainian Ironbelly – Nowegian Ridgeback -Known Dragon Breeds

Astronomy, Herbology, Flying, Potions, Transfiguration, History of Magic, Defence Against the Dark Arts – Charms -Core Subjects

Aragog, Fang, Buckbeak, Norberta – Fluffy -Hagrid’s Pets

Harry Potter, Nagini, Diadem, Diary, Ring, Locket – Hufflepuff’s Cup -Voldemort’s Horcruxes

Sirius Black, Peter Pettigrew, James Potter, Rita Skeeter – Minerva Mcgonagall -Known (not necessarily registered) Animagi

Cloak of Invisibility, Resurrection Stone – Elder Wand -Deathly Hallows

Dobby, Hokey, Winky – Kreacher -Known House-Elves