Seems that there are any new character added or not what i know.
On the Mega Pack, they deleted all of the Developers characters and memes that can be spawned.
The only good thing is that they added new 2 levels for both games and updated some sprites. But sadly, the removed more stuff thant new stuff (also, you cant spawn the Nintendo Wii u exclusive characters on the Switch ver.)
There is a other game called Scribblenauts Showdown, where they added characters but they are only avatars and is a board game if i remember well

Yeah, but like DC wise, did they add any new characters? Like Slipknot from the Suicide Squad, Apache Chief, Black Vulcan, Sun-Boy, Egghead or Polka-Dot Man. Or maybe even Typhoon, Hyena, Professor Martin Stein, Doreen Day, Cliff Carmichael, Gehenna, Pozhar, Bug & Byte, Tokamak, Silver Deer, Mindboggler, Goldenrod, Moonbow, Shadowstorm, Shoe Shine, Power Company, Stalnoivolk, Weasel, and Slipknot just for example.