All of the Gotham Rogues figures were made by Samq Jones.
Joker is made from X-Man, with a whole lot of sculpty to make just about everything on him, and painted cloth for his coat tails.
Penguin is made from Snaggletooth from the Star Wars Cantina 3-Pack, with the same materials as with joker, plus a toothpick in his nose and a piece of bubble pack for his monacle.
Solomon Grundy is made from Battle Blasters Beast using the same techniques as with Joker.
Mr. Freeze is Made from Marvel vs. Capcom Dhalsim, with a bunch of sculpy, and piece of pen for the gun, a bit of wire and bead container with a rubber band around it for the helmet.