I'm a relative newbie to Twine Sugarcube, but have made a couple of RPG games. I noticed that I was reinventing the wheel with core elements, so I made a set of templates that could be copied and pasted into ant game I started and then be customised to suit the game. I thought that other newbies might find them helpful. They are:
A Character Select System (name, gender, race and class).
A Simple Inventory System (pick up, dipose, store and retrieve).
A Shop (buy items if sufficient gold).
A Tavern (buy drinks, talk to people).
A Crafting Shop (blacksmith and alchemist).
A Combat System (punch, kick, use weapons, use skills and use potions).
Click on them to run in a browser (images in base64) or load into Twine Sugarcube.
Feel free to customise and adapt as required.
A zip file containing all six templates can be downloaded from MediaFire at: