CardName: Mindswell Matron
Type: Creature - Vedalken Wizard
Rules Text: Players have no maximum hand size.
Players can't discard cards.
Set/Rarity: Temporary Allies Rare
I have used that second ability in a card. Why is this ? Because of the synergy with looting? Note that it's also anti-synergistic with looting cards that require you to do the discard as a cost. Besides, I wouldn't determine which color to place an effect by how well it would help that color.
Absent a good real card example, weird stuff that messes with high-level game frameworks feels inherently Izzet to me.