With only two known copies, its rarity makes it one of the most sought-after trading cards in the world
Secondly, you need nonland permanents that can tap for at least two mana
Dragons of Tarkir gave us five newcomers (Dragonlord Silumgar, Dragonlord Atarka, etc.), Core Set 2019 gave us retrains of the originals (Arcades, the Strategist, Nicol Bolas, the Ravager), Strixhaven added five more as the namesakes of the different schools (Tanazir Quandrix, Beledros Witherbloom, etc.), and the five metal dragons from Baldur's Gate were also given the double creature type (Ancient Bronze Dragon, Ancient Copper Dragon, etc.)
That's just like Nixilis's second ability, although worse since they get mana, and better since it's just -2 to -3
A buyer who receives a card in better-than-expected condition is happy
Card Rarity Breakdown of the Set This is perhaps the most important thing to know