Out of ${\mathrm{N}}_2\mathrm{O}, {\mathrm{SO}}_2 ,{\mathrm{I}}_3^{+}, {\mathrm{I}}_3^{-}, {\mathrm{H}}_2\mathrm{O}, {\mathrm{NO}}_2^{-}$  and ${\text{N}}_3^{-}$ the linear species are

${\mathrm{N}}_2\mathrm{O}: \text{N}=\mathrm{N}=\mathrm{O}$;Linear

${\text{I}}_3^{-}:$  with $2 \mathrm{bp}$ and$3 \mathrm{Ip}$around central atom [ $\mathrm{I}-\mathrm{I}-{\mathrm{I}}^{-}$] is linear.

${\text{N}}_3^{-}$ with $2 \mathrm{bp}$(stereoactive pairs) around the central atom is linear.