Perhaps pot worms?

What is the moisture level of that medium? Maggots, the larva of flies, need a fairly moist environment to hatch and live in.

kimmq is kimmsr

yes

Well, it's some kind of fly or gnat larvae. Not something you want to have.

I wouldn't mix any compost with seed starting media. There just isn't any need. Seeds have all the energy they require to sprout and get off to a good start. Your mix looks "muddy' and not very well draining. A mix of peat, vermiculite and/or perlite would work much better.