I am curious about some of my favourites.
• Extracting text from screenshots of websites and videos.
• Universal clipboard.
• And my long time favourite: Prerequisite is that I have the folder I want to save into already open in the Finder. When in a save dialog I use command tab to move to the Finder. Click and hold the folder I want to save into. Command tab back to the application with the save dialog while still holding and drop the folder on the save dialog. This makes the save dialog jump to the folder.