Here are some simple themes:
- Evil of __________
Let's try a few.
What about "Faerie"? What would vermin be in that context? How about little faeries themselves, flitting just out of reach until there is a large enough gathering of them that they are bold enough to attack. That's pretty predictable, how about little bluebirds that fly in and peck you, or butterflies that swarm you and start putting you to sleep with their touch.
What about "Magic"? Magic vermin might be blink rats that teleport to your shoulder and start chewing your ear off. Or maybe even more magic, little, floating orbs that sizzle with energy and sting when they touch. Or maybe a snake that cycles into a rat into spider and back again. Or maybe that would be more suited to Chaos.
In the end, this isn't giving us the specific monster-making help I would like, but it may be the best possible. Why am I posting this now? Because we'll need this table for the next step in making our dungeon together.