Adding Custom Section to One Page Themes

With the popularity of One Page themes, is there an easier way to add additional custom sections to the home page of these themes.

I know that there is a way to edit the php files of these themes and add the section but I assume that there is also a simpler way to do this.

I am talking about themes that dont allow, or do not have, a way to add additional sections if we want to. Something like the Zerif theme or the Parallax-One there, where the entire editing for the front page is done through the Customize option in the Appearance menu.

Is there a plugin that can help with this ?

Thanks for showing interest ??
Ram.