For the CD challenge, by "extremely well", would it mean as in synergizes well with mainly those cards (ie. BE synergizes extremely well with creatures with less than 3 attack and no ability), or that it synergizes with a multitude of cards, but just so happens to synergize well with those specific cards (ie. Quint works well with basically everything, but it can also synergize with UU cards)?
The combination must be good enough to significantly make someone want to combo those cards, while not being strictly better in a different combo