Optimus – valid option, likely best, dudes a great leader

Caesar – would not lead humans

Captain America – Valid option, depends on the version though

Rick Grimes – he’s badass but he’s also just a dude surviving, no commanding experience

Xeno Scum – Xeno Scum

Kratos: actually led armies once upon a time but old him was also a blood thirsty monster so he might create more war but even so, valid option