First navigate to System Preferences > Keyboard > Shortcuts
You can use any of them in here
Just set them to the shortcut keys listed above
#How to make your own (to launch applications, quit all, etc.)
Navigate to Automator > New Document > click Service > Choose
Now we have to setup our shortcut
Here's how to setup the Quit All Shortcut
In the right window select the Service recieves dropdown > select No Input
At the top left click the Name (Search) > type quit > click and hold Quit All Applications > drag to the right hand box (under the Service Recieves)
IMPORTANT You have to click the Run button at the upper right hand corner in order for these to actually work.
Now click File > Save > save it as Quit All Apps (or whatever you want) / you can also just exit out and it'll ask you if you want to save
Navigate back to System Preferences > Keyboard > Shortcuts
The new shortcut can be found under services, set it to one of the shortcuts I listed above and done
The same applies for applications in the Name (search) just type the application you want to have as shortcut. Don't forget to run it, then do the same steps
to set it up as a shortcut.