Fungi of marine origin are frequently considered as possible sources of bioactive substances. Around 1500 species of marine fungi were estimated to exist in 1996, and by 2011, estimations of diversity were expected to comprise around a thousand species. Endophytic fungi have sparked widespread attention due to their potential to synthesize novel bioactive chemicals with a variety of biological characteristics. Novel compounds produced by endophytic fungi, like penicillin and paclitaxel, made way for the study of novel bioactive substances with potential for industrial use. This chapter gives insight into antiviral, antiprotozoal, and antituberculosis compounds. Antiviral compounds provide effective actions by acting against some human pathogenic viruses primarily by inhibiting viral replication within the body. The worldwide severity of protozoan illnesses is rising, compounded by a lack of effective treatment due to medication resistance and the toxicity of existing antiprotozoal treatments. In this review, we have compiled the chemical makeup and pharmacological responses of recently discovered organic molecule compounds in opposition to five prevalent protozoan organism diseases. Another disease covered in this review is tuberculosis (TB), a contagious illness triggered by the infection Mycobacterium tuberculosis (Mtb), which makes up one of the world’s top ten causes of mortality and the biggest cause of death from a single transmissible disease. Tuberculosis treatment is challenging and requires early identification, accurate and effective chemotherapy regimens, and drug resistance testing. A wide variety of fungal species and their metabolites have potent activity, which is widely discussed in this book chapter.