DUNGEON MASTERs!
I’ve found a simple but very interesting idea from Nathan Haslé: use swarms rules for crowd.
You can semplify dozens of low level adversaries all in once where the “strenght of many” could be a dangerous obstacle for your party.
When I was reading these few pages I start wondering about a band of unhandy bandits, a flock of angry baby goblins… a Zombies horde!
Download the pdf here: https://goo.gl/DaX66R
Some examples