While we're talking keyboards, what about emoji? Every messaging app has a different interface for them, some like Discord and Whatsapp allow you to use :smile: shortcuts, but the enumerated names are different across apps. I've occasionally gotten a dedicated OS emoji picker to show up on my Mac, but I don't know how.
On Ubuntu Cinnamon, I managed to create keyboard shortcuts for the 8 or so emoji I use the most by binding something called a "compose" key and modifying a .XCompose file, but it still took other config file gymnastics to make it persist between X sessions.