single key keyboard shortcut run-or-raise applications I just came from linux world (xfce4), where my keyboard workflow consisted of mapping 


F9 to terminal app
f10 to firefox
f11 to emacs


Upon pressing, the corresponding app would a) get focused (raised) or b) started. I achieved that by using wmctrl.

Can I achieve this natively in Sierra or is there an app for that?
There's no direct way to map an Application launch to a key command, but it can be achieved without too much difficulty.

To break it down into its components, you need  


A Service, which can be key-commanded  
An Applescript, to contain the actual launch command
An Automator workflow, to contain the Applescript
The actual key-command.


It might sound hugely long-winded, but it's simpler than building your own .plist


Launch Automator, from Applications  
Select New Document, then Service  
On the left, search 'applescript' &amp; drag Run Applescript to the main panel
  
Replace (* Your script goes here *) with tell Application "Terminal" to activate
Using activate will launch the App if it is not running, or bring it to the front if it already is.
[subsequent Services you generate will use each of your desired Apps in this line]  
Click at the top where it says 'Untitled' &amp; give it a suitable name. The destination will be already correct for Services.  
Hit  Cmd ⌘   S  to Save.
At the moment I'm seeing a new behaviour I've not noticed before, under 10.11.6 - Saving isn't automatically installing the service. Closing the Workflow window, then re-opening from File menu > Recent then gives the option to install it. ymmv.
Go to System Prefs > Keyboard > Shortcuts > Services &amp; find your new Automator Service [probably down towards the bottom of the list under General.
Make sure there's a checkmark to the left of it, then click none/add shortcut, to the right &amp; add your F-Key
Make sure your pref in System Prefs > Keyboard > Keyboard is set to use all F1, F2 etc as standard function keys - otherwise you'll have to use Fn/F-key instead.




Rinse &amp; repeat for your other required Applications.

After comments:
Running Services in this way may require Automator to be checked in System Prefs > Security &amp; Privacy > Privacy > Accessibility