Keyboards shortcuts for hidden characters
Use Option & Shift keys to access hidden characters in OS X
For even more hidden characters and emojis, use the Fonts panel and click on Action (gear) > Characters... or press 'Ctrl-Command-Space' to reveal Character Viewer.
Select a category from the side panel
Select and then Add to Favorites
You can access even more categories by clicking on Action (Gear) > Customize List...
Use this in conjuction with 'Text Replacement' to automatically replace characters.