Mac Dock Too Cluttered? How to Group and Tidy 30+ Icons
Start by cutting what you rarely open. Then group the rest: put folders on the right side of the Dock and show them as stacks, and keep app shortcuts in a folder of aliases. Apple's Dock has only two built-in dividers and won't take folders on the apps side. For labeled groups, as many dividers and spacers as you like, or several docks, use an editor such as Moor's edit mode (Control-Option-E).