Neomicrons are arbitrarily tiny particles that compose the structure of a neoid, and they are what makes them so stable. Every neoid has three neomicrons, and despite the shape of neomicrons being triangular, they sort of act like rods that prevent neoids from cataclysmically exploding.
They also control the temperature of a neoid. Outside disturbances that change the temperature must hit the neomicron to change it.
Because neomicrons are inside of neoids, they are almost impossible to observe, as it requires opening the parent neoid, which may only be possible with other neoids, and even then, there is such a tiny window of time to remove the neoid chain used to create the opening and take a picture of a neomicron inside that it's already exploded. That means you have to create a new neoid chain, which is hard to make as neoids are hard to get to stick together, and a naturally forming neoid chain is inapplicably hard to find.
As they are contained by neoids people will never know of their existence(due to the classification level of the original files). However, if they didn't exist, the commonly found 4, 16, or [cardinal number] of fundamental forces would not work the way they do in usual verses, and would never have existed in the first place. Neomicrons are far more stable than neoids, but are still unstable, as any minor interaction on the scale of a neomicron could destroy them instantly.