I've found a couple of interesting formulae for the characteristic polynomial $c_A(x)$ of matrices in the form of $$A= \begin{pmatrix} 0 & 1 & 0 & 0 & \cdots & 0 \\ 0 & 0 & 1 & 0 & \cdots & 0 \\ 0 & 0 & 0 & 1 & \cdots & 0 \\ \vdots & \vdots & \vdots & \vdots & \ddots & \vdots \\ 0 & 0 & 0 & 0 & \cdots & 1 \\ 1 & 0 & 0 & 0 & \cdots & 0 \end{pmatrix} $$
That is $$c_A(x)=(-1)^n(x^n-1)$$
Are there any similar formulae for some special kinds of matrices for quick reference?