A card usually earns that status by being a power benchmark, the first clear example of an effect, a tournament-defining staple, or a card everyone references in conversation
I genuinely think that could be alleviated if Wizards ever printed another Vampire commander in his color combination, but its impossible to say right now (and they apparently are hesitant to do it because they dont feel like it would be wanted)
It can't enter the battlefield attached to a nongreen creature, it can't be moved onto a nongreen creature, and if the creature it's attached to stops being green, the Aura is put into its owner's graveyard
Powerful Jumpstart card Bruvac the Grandiloquent is seeing a return in MTG Ravnica Remastered, bringing mill decks back to the forefront
Magus Lucea Kane Secondary commander of the Tyranid deck and leader of your local Genestealer Cult, Lucea will quickly pump your army and provide power for your variable strength spells, something her Jeskai colors are famous for