This is like having a Doubling Season or Parallel Lives right in the Command Zone, which is an intense amount of power at your fingertips right at the start of the game
Think of it like a Hatebear strategy except our win conditions are big ol' fuzzy monsters
Most of the likely zero drop spells do fall into that range, but there's a handful of possibilities like Everflowing Chalice and Zuran Orb that I could see showing up but aren't huge powerhouses
Sample Decklist The Commander At a glance, Zack Fair seems like a decent support card, but a terrible commander: hes a simple 0/1 Human Soldier that costs one white mana and comes into play with a +1/+1 counter , and later you can sacrifice him to give his +1/+1 counter and one Equipment to another creature
The Showdown can be cast for 6, but the fact that its a modal card makes it so, so much better
Either that, or he just makes a permanent and game ending Glorious Anthem