I think this is a really good list of open-source apps you will enjoy. I made sure not to include any repeats from my previous Top 10 list.
It’s incredible that we live in a time where people give up their free time and effort to create wonderful applications for everyone to use. They should be compensated too, so I will leave links wherever possible if you want to donate to these amazing developers.
Note that for most of these apps, you will get a warning that they have been downloaded from the Internet and some will require you to explicitly allow access by visiting System Settings => Privacy and Security.
You can download applications by clicking on the links, or if you have Homebrew installed, I placed a one-liner for each one.