Image: Batman the Animated Series, WB
There are a lot of things from the movies and TV shows making their way into the comics these days, since both influence each other in an endless marketing cycle. This list is about characters who, these days, are important enough to the original comic book world they were spawned from that it's genuinely strange to think they weren't always there.
HERBIE was introduced in the 1978 animated Fantastic Four TV show because the Human Torch was unavailable (he'd been licensed for a solo movie). And because "Fantastic Three" does not alliterate, the decision was made to add a little robot to the team. He was then exported to the comics where, in true mindbending style, his origin was that his look was based on an in-universe Fantastic Four cartoon based on the in-universe Fantastic Four comic the "real" team had licensed their likenesses to.
(Comics!) These days, H.E.R.B.I.E. (Humanoid Experimental Robot, B-type, Integrated Electronics) gets to spend his days guarding Franklin Richards.
9) Terry McGinnis/Batman Beyond
The reason Terry, future Batman, is ranked so low on this list isn't because he isn't awesome. It's because Terry, created for the cartoon Batman Beyond, is still a pretty rare sight in the main comics universe. Terry became Batman in a possible future Gotham by basically stealing the batsuit from an old-as-hell Bruce Wayne, who eventually decides to mentor him in the role he'd given up. (In the comics, it's not Bruce, but he is still mentored into Batman.) Terry's maturing Batman made for great TV and we can only hope for him to get more time in the comics.
8) Mercy Graves
Mercy started in Superman: The Animated Series as the personal assistant and bodyguard of Lex Luthor. Three years after showing up in animated form, she appeared in the comics also as Luthor's bodyguard -- minus the chauffeur outfit she had in the show, plus a possible background as an Amazon. She also got more interesting character development in the comics, including an arc where she tried to atone for her bad actions.
7) Agent Coulson
Phil Coulson started out as a generic SHIELD agent in Iron Man, became the connection between the Marvel universe by popping up in most of the Marvel movies, died to bring the team together in Avengers, and then got resurrected to star in a TV show. And yet, somehow, the version of Coulson in the comics is even more badass.
He was an Army Ranger and best friends and partners with Marcus Johnson, who turns out to be the son of Nick Fury. He's put in charge of SHIELD's Special Ops division and is basically a living legend in the Marvel universe. No, really -- that's how he's described to Deadpool. An honorable mention goes to the whole Agents of SHIELD crew, who have also migrated from the small screen to the comics.
Kaldur'ahm was the version of Aqualad who appeared in the Young Justice animated series, and was such a good influence that the team chose him as their leader. He was also the son of the Aquaman villain Black Manta, and a lot of the second season story revolved around that connection.
A different version of the character -- with a backstory that included being raised on land ignorant of his heritage -- technically debuted in the comics a few months before the show. But the character had been created for Young Justice, the show just had a later premiere date than the comic had a release date.
5) Renee Montoya
In the same vein, the Gotham City PD detective Renee Montoya was also originally created for an animated series (Batman, in this case), but, because of the way the dates worked out for those things, the comic version technically premiered first. Her first appearance in the animated show had her as a new cop, just encountering Batman.
In the decades she's been in the comics, Montoya has been a leading character in Gotham Central, struggled with her family accepting her sexuality, left the GCPD, done a stint as the Question, and been a member of Batman, Inc. She's now as much a fixture in the DC universe as anyone, despite being conceived for the cartoon.
4) Laura Kinney/X-23
X-23, the female clone of Wolverine who's due to show up in Logan, didn't first appear in the comics as an attempt to invoke Rule 63. She was actually created for the cartoon X-Men: Evolution as a way to make the character of Wolverine relevant to the young kids that were the target demographic. (Yes, there was apparently a time when Wolverine wasn't considered the be-all and end-all of a non-comics X-Men story.)
She's not just the inverse of Wolverine in terms of gender, she's also someone who knows exactly what she's done and who she's killed as a result of the program who made her. The comics have had her explore a hard-won humanity and given her the Wolverine mantle.
3) Jimmy Olsen and Perry White
The Daily Planet's staff mostly came from 1940s radio show The Adventures of Superman. Although an unnamed copy boy in an earlier comic could be claimed to be the first appearance of Jimmy Olsen, his name and personality definitely came from the radio show. And thus Clark and Superman's photojournalist friend was born. Clark's boss at the Daily Planet, editor Perry White, get created in the exact same way. The Superman radio show also debuted Krypton, too, by the way.
2) Barbara Gordon/Batgirl
Batgirl was the biggest surprise on the list and one that's a little less cut and dried. There was both a Batwoman and a Bat-Girl prior to the 1960s, created at love interests for Batman and Robin, respectively, but were erased in 1964 for being too silly. The Batgirl that most people know and love is Barbara Gordon, the daughter of GCPD Commissioner Gordon, who was created for the '66 Batman TV show.
The producer wanted to add a female character to the show to bring in a bigger audience of women and girls and it was an executive producer of the show that suggested the character be the commissioner's daughter.
The name and look the show optioned from concept art they saw at the DC office. Now Batgirl technically debuted in the comics first -- in 1967's Detective Comics#359 -- just before Yvonne Craig first played her in the Batman show's third season. So it's a bit muddled, but suffice it to say, Barbara Gordon wouldn't have existed without the TV series.
1) Harley Quinn
She's the poster child for all these characters. Harley Quinn was originally created for Batman: The Animated Series because it was thought a sequence they had planned for the Joker would work better with a female villain. The Joker ended up performing it anyway (it involved a giant cake and a hostage situation, for whatever it's worth), but the character of Harley was born.
She's all over the comics as a villain, a semi-reformed anti-heroine, the Joker's abused love interest, or having moved past the Joker entirely -- but no matter her incarnation, it's actually hard to imagine the DC universe without her. And, of course, she steals every story she's in. It should be no surprise that the announcement of a Harley Quinn-led movie was the biggest result of the Suicide Squad film.