There is also the issue that many red white and red+white decks have to deal with is that they rely heavily on artifacts to do things thier colours can't and since everyone can use those cards they tend to rise in price more than the millionth big green dude.
Pioneer:UR Pheonix
Modern:U Mono U Tron
EDH
GB Glissa, the traitor: Army of Cans
UW Dragonlord Ojutai: Dragonlord NOjutai
UWGDerevi, Empyrial Tactician "you cannot fight the storm"
R Zirilan of the claw. The solution to every problem is dragons
UB Etrata, the Silencer Cloning assassination
Peasant cube: Cards I own