Turning all your creatures into mana dorks sets up some explosive turns, especially paired with greens big card draw spells like Last March of the Ents and Rishkar's Expertise
And, of course, the amazing new Sagas from Dominaria like History of Benalia are also historic
I consider Walking Ballista to be the best example of a card to have in your Cube that gives players wanting to stay open something powerful to draft
Azula Always Lies Confront the Past Dai Li Indoctrination Decorum Dissertation Desperate Plea Inkling Summoning Necrotic Fumes Ozai's Cruelty Pest Summoning Ruinous Waterbending Scarring Memories
Sygg, River Guide Sygg, River Guide can be a good merfolk commander
Slinza, the Spiked Stampede Slinza, the Spiked Stampede is a true beast commander, providing cost reduction, a pump ability, and removal all at once