MacMoji is one of the most used and also overlooked addons that I use across my Apple devices. For those of us who are used to typing emojis 'inline' a la Slack / Trello etc (as opposed to bringing up an emoji specific keyboard or emoji picker), this is a great productivity extension. Not having to switch out between input methods saves a lot of accumulated time.
It's dead simple to install: just drag and drop from the plist file:
Installation takes seconds, and if you have mutiple Apple devices, the text replacement syncs to them as well (except for Apple Watch). Installers are also available for Keyboard Maestro and TextExpander, both of which I use, but find that the plist file method is better geared for those of us who move between devices.
MacMoji is amazing, updated frequently, free, and ultimately an amazing must-have for text-based emoji entry.