Batman and any IP's that they are about to lose their rights to. That's it.
DC's goal is to make money. Batman is the only Franchise that makes any money that's worth anything from Comics.
Superman etc Dc doesn't need to put out comics save to ensure that it doesn't fall into the public domain
Logically, the 10 books they need to publish would be their 10 best selling ongoing series. Based on most recent sales data, that would be the below:
Batman
Flash
Detective Comics
Justice League
Batman/Superman
Superman
Action Comics
Green Lantern
Legion of Super Heroes
Wonder Woman
The crazy thing is that the lowest selling of those (Wonder Woman) came in at number 66. There's that few ongoing DC books in the top sellers list. Most of what they are selling are minis seemingly.
Last Read: Aquaman & The Flash: Voidsong
Monthly Pull List: Birds of Prey, Daredevil, Geiger, Green Arrow, Justice Ducks, Justice Society of America, Negaduck, Nightwing, Phantom Road, Shazam!, Space Ghost, Suicide Squad: Dream Team, Thundercats, Titans
Heroes ... there aren't 10.
1. Batman
2. Superman
3. Wonder Woman
4. (a) Flash
5. (a) Green Lantern
6. Aquaman
Titles
1. Detective Comics
2. Batman
3. Action Comics
4. Superman
5. Wonder Woman
6. The Flash
7. Green Lantern (Corps)
8. Aquaman
9. Justice League
10. Titans
1. Superman
2. Action
3. Batman
4. Detective
5. Wonder Woman
6. Justice League
7. Flash
8. Green Lantern
9. Aquaman
10. (Teen) Titans
01. Superman
02. Action Comics
03. Batman
04. Detective Comics
05. Wonder Woman
06. Green Lantern
07. The Flash
08. The Justice League
09. Aquaman
10. The Teen Titans
Detective Comics
Action Comics
Aquaman
Green Lantern Corps
The Flash (Barry Allen)
Flash: Speed Force (Wally & the rest of the speedsters)
JLA
The Titans
JSA
Showcase
Wonder Woman
"My name is Wally West. I'm the fastest man alive!"
I'll try being nicer if you try being smarter.
I think the deal eventually got renegotiated. There was also one where she couldn't appear in anything unless she was also a star which prevented her from guest spots on other shows like Superman: The Animated Series. Marston was so focused on making sure she was respected he kind of shot her in the foot in the long run, but it's probably why she endured since she was never a high seller in print. Merchandise was her real draw.