My question concerns the Mumford-Tate conjecture for abelian varieties over number fields. I am not sure whether this question is better suited for stackexchange.

Most proven cases (that I am familiar with) show that the l-adic monodromy group is as large as it can possibly get because of the conditions imposed and has the same rank as the Mumford-Tate group. A notable exception is the paper of Zhao for four-folds with endomorphism ring $\mathbb{Z}$ which starts out with abelian varieties such that the derived subgroup $G_l^{\mathrm{der}}$ of the $l$-adic monodromy group is a product of three copies of $SL_2$ and shows that the same is true for the Mumford-Tate group (as opposed to the latter being $GSp_{8}$). Are there any other known results of this type?