There are severals. But in brief, two common examples are presented globally, earth worms and Oribatid mites. Oribatids are soil dwelling mites. Which have a great role in C/N ratio and soil's nutrient cycle. As well as earth worms.
These two groups were suggested to be bioindicators of soil health and detectors for pollution.
You can read more about these groups and more in the GEO BON initiative (www.geobon.org). Also, e-atlas series for soil biodiversity has been published of European, African and Asian soils available for free via the GEO BON and SoilBON.
Personally, I am highly recommending the Soil biodiversity simple articles, which have been produced in the Frontiers For Young Minds (available online in English and other languages) at www.idive.de. In these articles you will find large data that dealing with the soil invertebrates and their interactions.
I will advise the Soil Biology Guide (book), by Daniel L. Dindal, WILEY 1990. It is an old book now, but it still the best with many excellent book chapters addressing your question.
[BOOK] Soil biology guide
DL Dindal - 1991 - books.google.com
A comprehensive study of the biology, taxonomy, and ecology of each of the soil biotic groups. The first chapter presents an ecological approach to soil studies.
Organisms like earthworms, fungi, bacteria, and other decomposers play crucial roles in enriching soil by recycling nutrients. They break down organic matter, releasing essential nutrients for plants and promoting soil structure. This microbial activity is vital for maintaining healthy soil and biodiversity.