Green Arrow - In The Superfriends' episode "Gulliver's Gigantic Goof," Green Arrow made his only animated appearance. Voiced by Ted Knight, the same man who gave Aquaman character, Green Arrow starred in most of the episode. He was true to form, capturing Ollie's light-heartedness of the 70s.
Felix Faust - Appearing in the Galactic Guardian's episode "The Case Of The Stolen Super Powers," Faust appears as just another diabolical magician, who is eventually shown up by The Penguin in an attempt to steal Superman's powers. Very weakly written, Felix Faust makes a poor appearance.
Jonah Hex - In the Batman episode "Showdown" Ra's al Ghul narrates a tale from the 1800s. In it, he tells of how a lone gunfighter thwarted his plans for a huge flying machine. One of the best Batman episodes in my opinion, it interprets Jonah Hex perfectly to animation, from his nonchalant attitude to his western drawl.
Zatanna - Entitled "Zatanna," this episode of Batman showed off some history of Bruce's training under "The Great Zatara," Zatanna's father. In the main story, Zatanna works with Batman, not knowing till the end that he and Bruce Wayne are the same. Possessing no truce mystical ability, Zatanna appears as a traditional magician, which worked well with the series.
Bat-Mite - Making one of the briefest of cameos, Bat-Mite appeared as a robotic creation of Carl Rossum in the Batman episode "Deep Freeze." In his appearance, Bat-Mite surprised Robin; if you look closely, you can also see Mr. Myxzptlk, Streaky, the Super Cat, and Krypto, the Super Dog, in the background.
Dr. Fate - The Superman episode "The Hand of Fate" showcased the Man of Steel working beside yet another guest star - Dr. Fate. Appearing in only about seven minutes of the show in costume, this interpretation of Dr. Fate held the right elements in the show, but seemed more to focus on his brooding attitude that who he actually was. The revamp of his uniform was a nice touch, though.
Maxima - In the recent episode of Superman, entitled "Warrior Queen," Maxima made her first animated appearance. Given a shallow interpretation, Maxima was translated into a poor imitation of Xena; the only difference being her desire for Superman. The only really good part of this episode is near the end, where Lobo makes a cameo... watch it and see.
Bane - Starring in his own self titled episode, "Bane" was the animated interpretation of the "Knightfall" storyline. Fitting in with the Batman: TAS mythos, Bane was hired by Rupert Thorne to break the Bat. The most tense scene in the episode happened when Bane lifted Batman over his head and said the dreaded words, "I will break you." Fortunately, Batman escapes this time, beating Bane to a pulp. This interpretation of Bane is about near perfect as he will ever be off of the comic page; his accent fits very well with the origin. The only drawback to me in this appearance was his costume, more reminiscent of a wrestlers uniform.
Steel - Possibly to promote the theatrical release as well, Steel made a recent appearance in Superman, adding to the supporting cast. In "Heavy Metal," John Henry Irons creates his suit of armor to aid Superman in Metallo's new gang. A good animated showing of Steel, his armor suit looks nicely sans cape.
With Batman and Superman making good runs on television six days a week, fans could be in for more brand new appearances by DC characters. Already, Nightwing is a regular on Batman; who could be next?