Currently, I just have a handful of features and some views, but this is built upon years of work with small businesses and seeing what works. I’ve also got some basic integration for Buffer to allow time release of posts into your social streams.
Setting up file attachments in D6 for content types required a core module to be activated. You could sill add a CCK field for files or images or whatever, but the default attachment system (“Upload” module) was the place to go and often one of the easiest.