While not the greatest on value, its worth a note just for the spot-on design
Brokkos, Apex of Forever Wanna mutate with a big nasty over and over again from your graveyard
If, for some reason, the permanent doesn't have the squad ability when it's on the battlefield, the ability won't trigger, even if you've paid the squad cost one or more times
Even if someone is Tormod's Crypt'ed or Bojuka Bog'ed and devoid of a graveyard, it'll still bring the heat
Beyond that it's mostly generic upgrades like Smothering Tithe, Teferi's Protection, better land upgrades, better removal, the usual
Apocalypse Hydra Apocalypse Hydra is a good reason to ramp, because for 7 mana you get a 10/10, which is already powerful