Yeah, I think Star Wars is probably the winner. Sooooo many PC games, and a ton of console games.
The Musou games (Dynasty Warriors/Samurai Warriors) is a pretty hefty series to collect for, too. 8 Dynasty Warriors games. And then each of those have both an "Xtreme Legends" series and an "Empires" series. Xtreme Legends started with DW 3, and Empires started with DW 4. Then you have the 4 Samurai Warriors games, and one of those had Xtreme Legends spin-off, too, as well as a "State of War" spin-off. There's also the Orochi Warriors series, which there are 3 of, which combine the characters of the two game series into one. And finally there's Hyrule Warriors.
So by my count that's 29 Musou games.