I think the Paul Dini/Bruce Timm DC animated universe needs to be mentioned for bringing a lot of lasting influences to the comics. A number of original characters from the shows found their way into the DC Universe proper--Harley Quinn, Mercy Graves, Renee Montoya, Lock-Up, and probably a few others.
Lock-Up made it to the comics? Did Dini (who created the character) introduce him into the comics, or was that some other writer?
It's also worth noting that Paul Dini's current (recent?) run on Detective Comics
has a very DCAU flavor, and has introduced DCAU concepts such as the Penguin going straight(ish) and opening the Iceberg Lounge.
Meanwhile, the new version of Brainiac that's just been introduced in the Superman comics seems very much like the DCAU version.
DCAU takes on established characters heavily informed the comics as well... Chief among these would be Mr. Freeze, who never had much of an interesting origin/backstory prior to the animated version. The tragic ex-scientist seeking to revive his wife has become the accepted comics version of the character.
And beyond. Batman and Robin
used that origin as well, although it was a total mismatch for the tone of the movie and the casting choice of Arnold Schwarzenegger. (There were initial rumors that Patrick Stewart would play the role and that it would be closer to the tragic B:TAS version.)
Furthermore, the animated version of Green Lantern John Stewart led to a revival of that character in the comics. Prior to JL/JLU, John hadn't been a ringwielder in the comics for some time, serving as an occasional supporting character in the Green Lantern books. After the show gained popularity, John returned to active duty in the books, strongly resembling the animated incarnation in costume and hairstyle. Since then, the animated Stewart's Marine Corps background has been retconned into the comics, as well (the comic Stewart was an architect by trade--which remains the case--but he had never been depicted as having prior military service until recently).
Interesting -- I didn't know that. Good to see Stewart getting more attention in the comics. (Though is Earth ever
going to get a female Green Lantern??)