For my leagues I generally like to utilize alternate uniforms for low-level rookie teams. I noticed that as of now the new 2019 Marlins alternate jerseys had yet to be done so I made up a couple for the GCL/DSL Marlins using their spring training and alternate black jerseys, respectively. As far as I know I assume that the DSL team uses the regular Marlins cap but feel free to correct me if you find any pictures showing otherwise.
Spring Training/ GCL Marlins:
Alt/ DSL Marlins: