I could work on getting the deck list if that is something you are interested in.

There are a few extra combat effects like Bloodthirster or Port Razer to get more triggers of Calamity.

I run a decent amount of cards that untap/gain control/ grant haste like conscripts. They are good at removing blockers, untapping Calamity for the above additional combats, or granting haste to a big creature that I might drop onto the board.

With these conscript style creatures I can reuse creatures with tap effects like Jaxis, Krenko, Mob Boss, and Heartless Hidetsugu. Jaxis filters cards in hand, Krenko lets me go wide, and Hidetsugu can let me quarter life totals out of nowhere.

The cmc run a bit high on creatures, so I supplement the early game with adventure cards like Fang Dragon, Grabby Giant, and Two-Headed Hunter. They are not super big creatures, but if I get two of them from Calamity they are enough to apply pressure.

Herigast, Erupting Nullkite is a great option for using the tokens post combat to be able to drop a bigger creature for cheap or recast my commander after it has been hit with some removal.