The trefoil knot is tricolorable: In a projection, with at least two colors used to color its "strands," at every (degree-$3$) crossing, either all three colors come together, or all three strands have the same color. The figure-$8$ knot is not tricolorable: It needs $4$ colors.
Image from Wikipedia article.
Q. Are there knots that require $k$ colors, for arbitrarily large $k$?
I assume the answer is Yes, in which case examples would be appreciated.
According to Breiland, Oesper, and Taalman, in this paper, Theorem 1 says:
This gives us that for any prime $m$, $T_{m,2}$ is $m$-colorable. I am sure that there are other good examples, but here is a positive answer to your question.