Saprotrophism is a life mode exhibited by microfungi. Saprobes are cosmopolitan and occur in various habitats and ecological niches dwelling on diverse substrates and this contributes to the high numbers of fungi. Being abundant in litter, soil and decaying matter, they play crucial roles specifically towards mediating carbon and nutrient fluxes. Saprobic fungi in forest ecosystems may be host-specific or have host preferences and revealing this phenomenon will provide insights towards predicting global fungal numbers. In recent years, elucidation of saprobic fungi has been revolutionized through advances in molecular phylogenetics and the availability of genomic data, particularly in the Asean region. High-throughput sequencing and metagenomic approaches have revealed that the mycota are more diverse than previously established in samples in tropical forest ecosystems. This review discusses the role of fungi as saprobes, their host-specificity and host preference, their importance in litter decomposition and nutrient recycling, and their global dispersal. Approaches to establish fungal prevalence in the current genomic era are also discussed.