Those cards that are somewhat more dependent on each other tend to be better for balancing the overall card advantage of Partner commanders, like Haldan, Avid Arcanist and Pako, Arcane Retriever
Morphling was too hard to handle, with the shroud that kept it from being killed as well as the flying, untapping, and flowing
Yuriko makes for a top budget commander deck too - little unblockable guys don't tend to cost too much
[7] For example, if a player opens Exhume, its an obvious sign that theres a draftable black deck in the reanimator archetype
Angel of Intervention Angel of Invention was heavily played in Standard thanks to its ability to make artifacts and for being a flying anthem
The black tutorsDemonic Tutor, Vampiric Tutor, and Liliana Vessare the most flexible, while Mystical Tutor and Enlightened Tutor require that your unfair target be a specific type of card