Full Character list has been revealed. The links will open up a window to a picture incase your memory is fuzzy. No Clock King, Clayface, or Scarface makes me sad.
1.
Alfred Pennyworth (voiced by Efrem Zimbalist Jr.)
2.
Amygdala
3.
Bane
4.
Batman (voiced by Kevin Conroy)
5.
Blue Beetle
6.
Catwoman
7.
Commissioner James Gordon (voiced by Tom Kane)
8.
Firefly
9.
Harley Quinn (voiced by Arleen Sorkin)
10.
Hugo Strange
11.
Hush
12.
Joker (voiced by Mark Hamill)
13.
Killer Croc (voiced by Clancy Brown)
14.
Killer Moth
15.
Maxie Zeus
16.
Mr. Freeze (voiced by Michael Ansara)
17.
Mr. Zsasz (voiced by Danny Jacobs)
18.
Oracle (voiced by Brittany Byrnes)
19.
Penguin (voiced by Paul Williams)
20.
Poison Ivy (voiced by Diane Pershing)
21.
Ra’s al Ghul
22.
Ratcatcher (voiced by Neil Kaplan)
23.
Riddler (voiced by Wally Wingert)
24.
Scarecrow
25.
Tweedledum and Tweedledee
26.
Two-Face (voiced by Richard Moll)