Looking at my cube, there is critical mass for: Goblins (R) Humans (all) Warriors (WBR) And, with some effort, other tribes could get critical mass running only cards that are cubeable by themselves, keeping the Poison effect to a minimum: Soldiers (W) Wizards (U) Shamans (RG) Vampires (B) I'm fine with dedicating 2-3 slots per color so each of these tribes have a Lord or some other linear effect as a nod to play them (Goblin Chieftain, Champion of the Parish, Chief of the Edge) but I don't want this cube to be mainly tribal, just have an extra layer of synergy that cares about the creature type line at a low opportunity cost
Thats especially true considering that Urza, in this state, is a Pre-Mending Planeswalker, when that power was even more potent than it is now
This active player base keeps older cards relevant and constantly introduces new fans to the hobby
Your commander can fill up the graveyard and spells like Living Death, Sun Titan, and Unburial Rites can reanimate them
Thats a bend
For example, if Elite Arcanist's enters-the-battlefield ability triggers twice, two cards are exiled
