What are the types of molecular orbitals? Provide a brief explanation.

(N/A) Molecular orbitals of diatomic molecules are designated as $\sigma$ (sigma),$\pi$ (pi),$\delta$ (delta),etc.
$1$. $\sigma$ (sigma) molecular orbitals: These are symmetrical around the bond axis. For example,$\sigma_{1s}$ and $\sigma_{1s}^{*}$ are formed by the linear combination of $1s$ orbitals. Similarly,if the internuclear axis is the $Z$-direction,the linear combination of $2p_{z}$ orbitals produces $\sigma(2p_{z})$ and $\sigma^{*}(2p_{z})$ orbitals. All these are symmetrical around the bond axis.
$2$. $\pi$ (pi) molecular orbitals: These are not symmetrical around the bond axis. Molecular orbitals obtained from $2p_{x}$ and $2p_{y}$ orbitals are labeled as $\pi$ and $\pi^{*}$. $A$ $\pi$ bonding $MO$ has larger electron density above and below the internuclear axis,while the $\pi^{*}$ antibonding $MO$ has a node between the nuclei.