I wanted to know if there are other "special" angles when using the rotation matrices in 3D. Looking at them I see that if the value of $\theta = 0$ or $\theta = 2\pi$ then the rotation matrices are the identity matrix, therefore vector doesn't change at all.
Are there other "special" values for $\theta$ to consider?
The rotation matrices are as follow:
$$ R_x = \begin{pmatrix} 1 & 0 & 0 \\ 0 & \cos \theta & -\sin \theta \\ 0 & \sin \theta & \cos \theta \\ \end{pmatrix} $$
$$ R_y = \begin{pmatrix} \cos \theta & 0 & \sin \theta \\ 0 & 1 & 0 \\ -\sin \theta & 0 & \cos \theta \\ \end{pmatrix} $$
$$ R_z = \begin{pmatrix} \cos \theta & -\sin \theta & 0 \\[3pt] \sin \theta & \cos \theta & 0\\[3pt] 0 & 0 & 1\\ \end{pmatrix} $$