Custom Generate Templates

I understand that I can modify the templates under “node_modules\ionic-angular\templates”.
Sometimes I want to “ionic g page home”
Sometimes I want to “ionic g mycartpage shopping-cart” (or a half-dozen other possibilities I have)

I tried adding a folder under “templates” but received “type must be one of…”

Is there a way to customize, override or enhance the template types?

Angular now has Schematics:

And example:

Thank You @robinyo for your response.
It was not immediately obvious how this helps me, though I have spent little time looking at it.

You could follow this process, without submitting to the community: