Took me a while, but I have managed to put together some kind of mockup for the Trolls as well.
Since I was afraid that people might go crazy about the specific types I listed despite of just making this just to show how the templates could work, I thought I’d add Jungle Trolls, Sand Trolls, Forest Trolls, and the ever-elusive Dark Forum Trolls. 
Enjoy!
https://i.ibb.co/ScJhrPN/subrace-customization-mockup-troll.jpg