This serves to be an ever-changing personal list of what to install if I ever redo my Ubuntu machine. Currently I am running Ubuntu 18.04 so can only guarantee compatibility with that version.
Comfortable Swipe – https://github.com/Hikari9/comfortable-swipe-ubuntu
Lets you map trackpad gestures to just about anything. Also comes with sensible macbook-like defaults
MellowPlayer – https://github.com/ColinDuquesnoy/MellowPlayer
Ever wanted a well integrated linux app for your music player of choice? Deezer? YouTube?
(Note: You will need to install pepperflash)
Visual Studio Code
Dash To Dock
Sound Input and Output Device chooser
Note: All extensions can either be downloaded from the gnome-extensions site or the integrated software store