Should this be a one time effect instead of a one turn? That is, is U too cheap to be able to play every Aura in your hand as an instant, or should it be U, you may play an Aura in your hand as an instant?

Actually, I’m starting to think that the ability may not need an activation or EOT limitation at all. Vernal Equinox was a rare, but this is more restrictive, more relevant to the set it’s in, and susceptible to more kinds of removal.

Consider this a narrow but conditionally powerful uncommon. You may not always want to first-pick it, but if you’ve managed to grab a few solid auras, he becomes a great accessory.

It's a bit hard to find using Gatherer, as the actual text and the oracle text are so different, but they printed almost this exact card in Tempest block: Rootwater Shaman

I'm not sure if the oracle wording for Rootwater Shaman is what would need to be used here. Regardless, the power level seems fine for Uncommon. It's basically in the mold of modern uncommon-build-around cards that usually fall around 5th or 6th pick unless someone is forcing the Flash-Aura archetype.

Good call on the template. Thank you, Shimmer Myr.

As an aside — I would be really excited if there was such a thing as the "Flash Aura" archetype in any format.

I believe Ravnica was as close as they got to making an aura-theme work, and even then you couldn't really build around them beyond Drake Familiar and Bramble Elemental. I think it might be good to put an equivalent aura-support card in both white and green, though maybe they should be spread out across the block similar to Burning Vengeance and Secrets of the Dead. But if you haven't already, you should probably make an Enchantress variant.

Worldwake had a pretty annoying Totem Aura thing going on. I think that probably counts as an aura theme.

Rise of the Eldrazi, yeah. But I'm not sure there were specific Aura synergies. Whereas Drake Familiar was specifically made to work with the common cycle of ETB Auras - Fists of Ironwood, Galvanic Arc etc.

There were several aura-assist creatures, actually. There was a white gazelle-thing that could fetch an aura from your deck, a white wizard/cleric thing that made all creature auras into Totem Armors, and the gnarlid that fucked you up when some ten year old dipshit put it in a no-brain deck with nothing but Totem Armors, gazelle-things, and wizard/cleric things.

So, I mean, generally speaking, there was enough stuff to consider it a sub-theme. Thing.

I guess I discounted RoE's aura-theme because I think that, as your memory attests, there wasn't really any finesse involved and you never picked Totem-Guide Hartebeest or the other white aura-helpers highly unless you had multiple Narcolepsy or Eldrazi Conscription. (W/G was an abominable combination in RoE, so you rarely had Hartebeest in your base-green Gnarlid deck.)

Whereas Ravnica had the aforementioned Familiar + ETB aura tricks, goofy things that you could do with Simic Guildmage, and the auras that boosted all other creatures with aura.