If veryy tiny and fly when you get near(rather than run) they are likely a type of soil/fungus gnat. Sundews are the best option for these, other carnivs do well, but sundews top every other method. Trust me on this. I've fought my wars against these lol.
If they run a lot and don't like to fly as much, then they are phorid, usually more likely to be found in bug bins feeding on old food and dead feeders though. These guys aren't attracted to the carnivs as much, but also unlikely that these are your problem unless something is rotten in your enclosure.
Then could be fruit flies, slower and larger. Easy to get rid of by removing their food source(usually fruit lol).
Lastly, if you have bromeliads, they will sometimes have a type of fly that leaves their larvae in the cups. They look like small house flies. Probably not the case here, but figured I'd throw it out there.