Reishi, also known as Lingzhi, is a fungus native to East Asia historically used in Traditional Chinese medicine. In certain contexts, such as in individuals reporting neurological fatigue, it may possess anti-fatiguing properties.
In a double-blind placebo-controlled study of 132 patients with neurasthenia, Reishi reduced ratings of fatigue by 28%. 
 Tang W, Gao Y, Chen G, et al. A Randomized, Double-Blind and Placebo-Controlled Study of a Ganoderma lucidum Polysaccharide Extract in Neurasthenia. Journal of Medicinal Food. 2005;8(1):53-58. doi:https://doi.org/10.1089/jmf.2005.8.53