Components are the building blocks; control_01 is a component. Yes you can make your own components. But that would be about coding components that have different behaviour or build methods.
But what you are describing sounds like a template. You take some components, assemble them like you want, and save them out to re-use? Yes! (They will not show up in your component list. Because that’s not the same thing.)
Just go mGear menu → Shifter → Export Guide Template.
You can select your guide, or a part of your guide. When you import it, it will put it under a new guide group. So I don’t know if you can really assemble a rig from modular templates. You’d have to do the reparenting stuff. (As far as I know.)
And you can code it too, so you can export and load the templates with Python. There’s a thread where that is being discussed. Guide Template Export Custom step