The Wikipedia pages for $E_6$ and $E_7$ list three series of groups notated as each of $E_6(q)$, $^2E_6(q)$, and $E_7(q)$: - The simple form, analogous to $\operatorname{PSL}_n(q)$ - The adjoint form, analogous to $\operatorname{PGL}_n(q)$ - The universal form, analogous to $\operatorname{SL}_n(q)$ Is there a fourth series analogous to $\operatorname{GL}_n(q)$?