Blood for the Baron!

So i have been collecting the Mcfarlane Walking Dead 5 inch figures. But i wanted to make some survivors not based on any specific characters. So i was wondering. Does anyone know any other lines that the heads would work Mcfarlane Walking Dead figures?

Halo? Gears of War? Or any other toy line? I don't want to have to paint them, so it will be a straight head swap, a bit of dremeling is fine.

Thanks for any help in advance.

Doctor Who 5" figures are the same scale, heads usually have a hole or peg, but either could be adapted