When synthesizing this list, I was looking at cards that are asymmetrical in their effect, hard to interact with, or have little ways to remove or stop them
Slime Titan full-art playmat
While there aren't enough Ninjas in Magic to make full-on tribal, being able to cheat Yuriko, the Tiger's Shadow into play with commander ninjutsu for just two mana repeatably makes it a bit like the infamously broken Derevi, Empyrial Tactician
7 Chandra, Hope's Beacon This is a very powerful planeswalker, but it does come with a relatively high mana cost
Maybe it was the introduction of Meren of Clan Nel Toth and later reanimation commanders that bumped it off the radar, but I was never really in tune with calling Karador a good Abzan commander
Being able to immediately cast a cheap tutor target is especially nice