As an alternative/complement to some notion of “#includes”, I would find a global pre-beforeRender() and pre-render() hook useful.
To recap my use-case, I have hardware buttons to trigger sequencerNext() and sequencerPrev() functions. Without any kind of pre-beforeRender() hook I’ve had to duplicate the button reading and debounce logic into every single pattern. This is obviously not the way you want to do it. It’s tedious and error-prone, and if I want to make a change to that code I’ve got to duplicate the change back into every single pattern in the playlist.
If I could simply implement a preBeforeRender() (and/or postBeforeRender()) function that would run pre- and -post the beforeRender() of every pattern, I’d have a single place to put that kind of code. I don’t have a direct use-case for preRender() (and I guess preRender2D() and preRender3D()) but I would guess they could be useful to someone, for example for pre-processing sensor input.