In literature, the synergistic effect of several substrates on feedstocks for anaerobic digestion/methane production is described for several substrates. Champost from mushroom production, vermicompost from worm composting/vermiculture and BSF (black soldier fly) larvae frass from insect production were therefore tested for this report for their synergistic effect. It was found that insect frass had a very high biogas/methane production as a single substrate. Addition of the frass led to a concentration dependent biogas production in mixtures with ‘old’ digestate higher than was expected based on the results of the single substrates. Champost resulted in some biogas production but from vermicompost hardly any biogas could be produced. Also, no synergistic or concentration effects could be noted from the latter two.