What tools are available to help organize iOS apps into folders?
You can use Apple Configurator 2, available on the MAS. It's intended as an enterprise tool for those managing lots of iDevices, but works just as well for one. It's fairly self explanatory and graphical in use.

Select your device, then from the menu bar: Actions | Modify | Home Screen Layout. There you can drag Apps about. You can even select multiple apps (Cmd-Click) and move them together.