Thats a key part of what makes Ancient Greenwarden so enticing, and the Chocobo costs half as much
Now to be fair to auras specifically and enchantments generally, there are commonly played Archetypes that run them (Voltron for auras to pump up a Commander, Enchantress enchantment heavy archetypes that have been around since Alpha)
Battle at the Big Bridge (Fatal Push) Fatal Push set a new bar for black removal when it came out in Aether Revolt, and it still sees plenty of play across formats like Pioneer and Modern that require the most efficient answers possible
There are already some reanimator elements and venture into the dungeon synergy
They also have a +1/+1 counters subtheme
Old One Eye Something something big dumb creatures oh wait, Old One Eye is a big dumb creature and creates another big dumb creature when it enters, can buy itself back later in the game, and gives all of your creatures trample