I was searching for a way to create rapidly new p5.js projects by template in Atom, but I have found none so I made mine and I hope it can help you as well:
https://github.com/MatteRohrn/p5jsProjectTemplateForAtom
It requires atom-smart-template in addition to Atom.
looking forward for feedback.
Thanks so much for making and sharing this.
Could this be listed with other Atom packages for Processing?
I’m glad to give my small contribution.
I have only put together the p5.js libraries and an index into a template to be used with atom-smart-template to generate a basic p5 project. I suppose that to release it as a package for atom I should first fork atom-smart-template. At the end it would be a re-labeled project supplemented with the template I created. On the other hand p5js-toolbar already includes the functionality to create a p5.js project from a template. I was experimenting with other extensions less impacting on the UI 
. Do you thing it may be and interesting package, or just redundant ?
Good question. I had assumed that contributing it would make it easier for Atom users to discover it the Atom package interface, but maybe you are right that people installing atom-smart-template and then downloading the your template is the way to go.
I see you point, releasing it as a package would make it easy to access in a consistent manner. But, since atom-smart-template is a flexible little app, to make it more visible I would make a video tutorial that shows how to use it for P5.js by downloading the template I have made rather than releasing a new package. That way I could also show how to personalize it even more by making the own template, for example with only the minified libraries or together with other libraries…