Which version of SketchUp? If it’s for SketchUp 8, where the advanced camera tools were in Tools and not plugins, you can get an installer from the links in this topic:
https://forums.sketchup.com/t/sketchup-pro-8-installer-download/43749/2
If it’s for 2017, it is a plugin, and should be here:
~/Library/Application Support/SketchUp 2017/SketchUp/Plugins/
How is it that you don’t have them loaded?