BBEdit, Sublime, TextMate, TextEdit (yes, it's actually useful in plain-text mode :P), CodeEdit etc.

My fav is SubEthaEdit and then there's CotEditor and these are just too good.

https://github.com/subethaedit/SubEthaEdit

https://github.com/coteditor/CotEditor

https://github.com/CodeEditApp/CodeEdit

(Note: And nope, Xcode isn't that. It's a monstrosity devs have to endure if they want to write and publish for Apple)