Here is the complete List of Apple Mac OS Versions till 2022. With release date and code names.
10. OS X 10.9 (Mavericks)
Released on October 22, 2013 OS number 10 debuts lot's of privacy features, majorly focused on password encryption and storage.
11. OS X 10.10 (Yosemite)
Released on October 16, 2014
Biggest redesign in many years. Things like thin fonts and new color schemes to the big shift like flat graphic design.
12. OS X 10.11 (El Capitan)
Released on September 30, 2015
El Capitan is faster, better, stronger than the previous OS, due to a major performance boost.
13. macOS 10.12 (Sierra)
Released on September 20, 2016
Apple shifts to the "macOS" naming. Again, more iOS things arrive, such as unlocking a Mac with your Apple Watch.
14. macOS 10.13 (High Sierra)
Released on September 25, 2017
macOS High Sierra adds a new video standard called HEIC and a transition to Apple File Systems.
15. macOS 10.14 (Mojave)
Released on September 24, 2018
Mac users can now move through their day-and-night routine, with the colors of the screen moving with them as they wish.
16. macOS 10.15 (Catalina)
Released on October 7, 2019 macOS Catalina Apple’s top-destination for media content into three dedicated apps Music, Podcasts, and Movies.
17. macOS 11 (Big Sur)
Released on November 19, 2020
11.0. Bringing a huge design change and transition to Apple’s M1 Macs, macOS Big Sur is the one to remember.
18. macOS 12 (Monterey)
Released on June 7 2021 macOS Monterey brings Shortcuts. The ability to set up quick actions with different apps to automate your flow.