This editorial discusses a special collection of studies exploring fungi that thrive in extreme and challenging environments around the world, from frozen Arctic lakes to salty lagoons and polluted soils. These fungi have evolved remarkable abilities to survive harsh conditions and can even help clean up contaminated environments or support plant growth in degraded soils. Researchers are discovering previously unknown fungal species and understanding how these organisms function in ecosystems, with potential applications for cleaning pollution, improving agriculture, and biotechnology.