Characters/Costumers in order of appearance:

Classic Harley Quinn Unhooded: Celia-Jade Mitchard

Formal Joker: Joseph ‘Kynin’ Christie

Riddler: roguewizard

"Alice" Harley Quinn: drquinzel

All photos by: hoperidesforeveralone

Event: London Super Comic Con 2012

Character: The Ridder, The Joker and Professor Pyg - DC

Costume/Worn by: Lee, Scott, and Mollins

Photo by: Ragemore

Under the Streets of Gotham

Characters: Riddler and Zatanna Zatara - DC Comics

Costumers:

FishyFins as The Riddler

Andserkiel as Zatanna

Photo by: Pete of CosplayFever

Character: The Riddler
Costume By: Lee Banks & David Mollins
Worn By: Lee Banks
Photo By: Stewart Loud
Event: Thought Bubble 2011

Submitted by: Cobblepot