Its a healthy mix of current resale value, the cultural impact each card has had, and a cards visual aesthetics, and also a bit of personal preference from myself as well (so just keep that in mind)
Many of the best removal spells are replacement removal, however
Clavileo, First of the Blessed Clavileo, First of the Blessed provides an interesting commander for vampire kindred decks
Historically a two mana 2/2 with Haste would be nothing to scoff at
while greens will replace creatures you lose with sapporlings, which will only be used in limited BG sacrifice decks, and reds will only be used in limited goblin decks because they have to dial it back during testing because its concepts are way too effective otherwise
At that point, youll be able to evaluate your average sale price and how fast things sell to get an idea of how much money youll make per card listed