4:58 I hope I didnt misunderstand the question you asked but the best 2 drops I can think of are Mosswood, Tenacious underdog, scyclave shade, scrapheap scrounger, maybe cankerbloom? If fable is bad green seems like the next best support color. Bronco is sick though its been great for me in mono-black waste not
my observations testing this deck: >RG seems a very bad matchup >would run double colored costs only in my 4 drops, because sometimes you need to play pathway on red and you can't cast liliana when you really need a removal spell >mutavault is awesome >i think red is not the right color to pair with black (maybe green?) >maybe try archfiend of the dross, since it blocks bird, is very good vs phoenix and 'good' vs vampires.