As mentioned Doomy3 is a good answer. However I don't think you can play Doomy3 in the current meta with Grymkin and Haley3 so prevalent.
Other good caster options are: - Grissel 2: Discord shuts him down. - Grissel 1: Carcophony shuts him down, though I'd argue she's not good enough.
If you don't want to dedicate a caster to it, I'd suggest looking at: Mulg or Dahlia and Skarath
A beast brick with Mulg in it can beat Butcher 3 but you need to learn the matchup and play it well.
Just wondering, why do you think Doomy3 is bad into grymkin and Haley3?
I guess grymkin have death knell to stop healing, but I've seen a lot of list with out and and the threat ranges seen to be pretty even.
Grymkin players are almost all playing Dreamer 4-6 heavies with Death Knell into Trolls. They also take the arcana that stops healing on top of the death Knell. It's pretty awful if your opponent knows the matchup.
Haley3 now getting played mostly in Gravediggers. Express Teams effectively stop your feat on anything that isn't a Gargantuan. Sadly I think New mulg is too expensive to run a Garg and Mulg so you end up running 5 heavy build and they shoot 1-2 heavies a turn off the board and you have nothing to deal with clouds. It's an absolute shooting gallery.