[bradw8]

If I wanted to make a comic to promote literacy among today's kids, are there any public domain characters they would like? Any thoughts?

[movielover]

It depends on the age group. For little kids, I would probably say funny animals. As the age increases, I guess branch out to sci-fi, super-hero. These are just suggestions

[bradw8]

Any specific characters or titles?

[movielover]

Look for yourself

https://comicbookplus.com/?cbplus=categories

[silversabrewolf]

Im currently collecting Forbidden Worlds..I'd say that series could broad appeal among children 9-13 yrs of age..It has a good mixture of Horror,Mystery,Sci-Fi..the Art is excellent..the stories as well.

[The Australian Panther]

To the original question, as a teacher I would suggest you ask some kids what would work for them. Find some kids, (that might take the question seriously), show them some comics and ask for their reaction. You very likely will be surprised at what you find out.
Interesting exercise: Photocopy a couple of pages of a comic with plenty of panels. White out the dialogue.
Copy enough pages for each student, cut out all the panels separately. give each student all the panels ( in a plastic bag or on a plate. Give them blank A4 paper. (So if you cut up two pages, give them each 2 blank A4 pages. And Glue.) Get them to glue the panels together in any order they like to make a story, then they write the dialogue. I Did this with High School students and a Phantom comic. They had a ball and  got very creative. Good thinking exercise.
Cheers. And have a good Christmas.