In LEGO Harry Potter: Years 1-4 there are many shops in which you can buy Extras and other Goodies. The shops are;Madame Malkin's Robes for All Occasions, Eylops Owl Emporium, Wiseacre's Wizarding Equipment and Gringotts. Also Knockturn Alley leads off down out of Diagon Alley, but only once you have learnt Reducto.
In LEGO Harry Potter: Years 5-7 the shops have changed slightly. In place of Wiseacres Wizarding Equipment, Weasely's Wizard Wheeses has appeared. Gringotts is now inaccessable but the other shops are present. Once again you can access Knockturn alley (without the Reducto spell).
Here are the character tokens found in Diagon Alley:
|Dexter's Diner | Mos Eisley Cantina ((LSWCS)) | Barnett College | The Batcave (LBM2 | LBM3) | Arkham Asylum | The Warehouse | Crystal Skull Hub 1 | Crystal Skull Hub 2 | Crystal Skull Hub 3 | Raiders Hub | Temple Hub | Crusade Hub | The Leaky Cauldron | Diagon Alley | Knockturn Alley | Hogwarts | The Resolute | The Invisible Hand | The Port | London | Campsite | Hogsmeade | Gotham City | The Batcave (LBM2) | Middle-earth | Police Station | LEGO City | New York | S.H.E.I.L.D. Helicarrier | Bricksburg | The Old West | Cloud Cuckoo Land | Octane Tower | The Watchtower | Hall of Justice | Hall of Doom | Moon Base | Zamaron | Odym | Nok | Ysmault | Okaara | Qward | Oa|