Any Aura card you find with Sovereigns of Lost Alara's second ability must be able to enchant the attacking creature as it currently exists. You need to check the Aura's enchant ability as well as any effects, such as protection, that would make it illegal to attach that Aura to the attacking creature. For example, if the attacking creature were an artifact creature with protection from blue, you could find an Aura with "enchant artifact," but you could not find a blue Aura.
If you choose to search your library but no applicable Aura card is left in your library (or you choose not to find one), then nothing enters the battlefield and you simply shuffle your library.
If the attacking creature has left the battlefield by the time Sovereigns of Lost Alara's second ability resolves, you can't put an Aura onto the battlefield this way. You may still choose to search your library just to shuffle it.
Last observed on Scryfall 2 months ago at $1.72. Over the trailing 90 days the price moved between $0.02 and $1.78 across 49 observations. Cross-checked across TCGplayer, eBay sold, Cardmarket EU, and Star City.
This printing is one of 3 catalogued treatments from UMA — the lineup includes Foil and Nonfoil alongside the standard finish. Across our catalog the Rarix library tracks every variant in the same family so collectors can compare price, scarcity and demand inside a single lineage.
Card #207 of *Ultimate Masters*, the set that shipped alongside the December 2018 Ultimate Masters release.
Card type: Creature — Spirit, color identity blue/white, printed at rare. Rares occupy the bottom-of-pack rare slot in standard boosters. Mana cost: {4}{W}{U} (6 converted). Keyword abilities: Exalted.
Legal in Modern, Legacy, Vintage, and Commander.
EDHrec ranks this card #10,380 in Commander, putting it in the fringe-play tier of the format's playable pool.
Illustrated by Donato Giancola. Rarix catalogs 770 other cards credited to this artist.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Donato Giancola
Card data via Scryfall. Rarix is fan-made; not endorsed by the rights holders.
If the attacking creature has left the battlefield by the time Sovereigns of Lost Alara's second ability resolves, you can't put an Aura onto the battlefield this way. You may still choose to search your library just to shuffle it.
If you choose to search your library but no applicable Aura card is left in your deck (or you choose not to find one), then nothing enters and you simply shuffle your library.
Any Aura card you find with Sovereigns of Lost Alara's second ability must be able to enchant the attacking creature as it currently exists. You need to check the Aura's enchant ability as well as any effects, such as protection, that would make it illegal to attach that Aura to the attacking creature. For example, if the attacking creature were an artifact creature with protection from blue, you could find an Aura with "enchant artifact," but you could not find a blue Aura.
The attacking creature is not targeted by either this ability or the Aura, so a creature with shroud can be enchanted this way.
