The original Teferi, Mage of Zhalfir design is nearly 20 years old by now and still quite powerful
My friends and I never played, but collecting and trading was all we did for months until a lot of my friends parents put a stop to the madness, sadly, and stopped purchasing cards for their kids
Add in Treasure and other ways of stockpiling and generating mana in these colors, and Rowan, Scion of War will be able to facilitate huge, explosive plays with relative ease
Many games utilize a set of keywords to simplify the card text, with keywords referring to common gameplay rules
It's notorious for a few reasons, and unsurprisingly, it's the usual story of scalpers ruining it for Pokmon trainers and collectors, causing chaos to the point that the museum stopped giving out the card
I don't think any other card on the list can say that it sees regular play in the most powerful format in the game