Harvestmen (Opiliones)
Arthropoda > Chelicerata -> Arachnida -> Opiliones
Okay, so maybe most harvestmen aren’t technically soil-based creatures, but they do predate on soil fauna, and they’re photogenic - that’s good enough for me! Loads of arachnid information, including how to contribute to UK recording schemes, is available at the British Arachnological Society’s website here.