For a heavily tribal-focused Commander to really be good, it needs lots of strong tribal support
Etali, Primal Conqueror Etali, Primal Sickness Etali, Primal Storm Ghalta, Primal Hunger Ghalta, Stampede Tyrant Nezahal, Primal Tide Tetzimoc, Primal Death Zacama, Primal Calamity Zetalpa, Primal Dawn
The first thing youve got to appreciate about The Abyss is that it has virtual haste
Mammoth Harness is another interesting attempt at MTG trying to do a 'vehicle' or 'mount', with the enchantment simulating a creature getting on the mammoth
However, effects which simply tell you to destroy a creature do not count as dealing it any damage
Sure, the creature sacrifices itself at the end of the turn, but attacking and forcing your opponent to sacrifice most of their board is usually enough to put you ahead and win the game