Much depends on the style of the room overall and the other elements in the space, but generally speaking, a Persian rug is classic and goes quite well with Buffalo checks. A simple sisal may also be a good option.

We don’t even know what color the checks are pictures are always a good idea.

If you buffalo check is bold, make the rug soft or solid. You don't want patterns and colors "fighting". Black and white buffalo check drapes + black rug or let the rug blend into the natural flooring color (whatever you choose for basic flooring)

You can have fun with it though!

Tell us more about what you have to work with.

I agree with everyone, let's see what we are working with!