Like most Magic: The Gathering cards, the value of Nethroi, Apex of Death depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Ikoria: Lair of Behemoths)
In fact, I tried searching MTG signed on eBay and sorted by price, high to low, hoping to find something that stood out
The one thing I have tried out since seeing this list is a 1-1 Ninjask line, which eventually made its way into my deck
Drannith Magistrate While innocent at first glance, Drannith Magistrate can negate win conditions from your opponent's decks like Emergent Ultimatum
The Duelists of the Roses 2001-09-06 Garvas (DM6) Yu-Gi-Oh
Ho-Oh ex is classified as a Crown card in the Wisdom of Sea and Sky set