To deal with the likes of Firefly Queen and Pharoah maybe a few Drain Lifes would help. The way I imagine it, you hit them with poison as soon as they come out, in most cases anyway, but their HP gives them enough turns to still get a few spawns on the field. The effectiveness of drain life though really depends on the abundance of Dark Quanta. If you have less than 10 most of the time, it probably isn't worth using
Maybe Plague could be good, though?