Cheapest priced copy (Kaldheim Commander): $1.79 at Card Kingdom, near mint, their price list as of .
Angel of Serenity 
Creature — Angel · 5/6 · Mythic · Commander 2015 · #58
Flying
When this creature enters, you may exile up to three other target creatures from the battlefield and/or creature cards from graveyards.
When this creature leaves the battlefield, return the exiled cards to their owners' hands.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
8 printings · $1.79 to $12.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2015 | 58 | Mythic | $2.49 | — |
| Commander 2021 | 83 | Mythic | $2.29Out of stock | — |
| Commander Anthology Volume II | 16 | Mythic | $1.99Out of stock | — |
| Kaldheim Commander | 18 | Mythic | $1.79 | — |
| The List | C15-58 | Mythic | $1.99Out of stock | — |
| The List | RTR-1 | Mythic | — | $2.79 |
| Return to Ravnica | 1 | Mythic | $2.79 | $7.99 |
| Secret Lair Drop | 1377 | Mythic | $8.49 | $12.99 |
4 rulings from Wizards of the Coast
- 1 October 2012If Angel of Serenity leaves the battlefield before its "enters" ability has resolved, its leaves-the-battlefield ability will trigger and do nothing. Then the "enters" ability will resolve and exile the targeted creatures and/or creature cards indefinitely.
- 24 January 2013If a creature targeted by the "enters" ability dies before that ability resolves, it will become an illegal target even though it may be a creature card in a graveyard when the ability resolves. It won't be exiled.
- 24 January 2013You choose up to three total targets from among other creatures on the battlefield and creature cards in graveyards. You may choose zero targets.
- 24 January 2013You choose the targets as part of putting the "enters" trigger on the stack. Because that ability includes "you may," you choose whether to exile the targets when the ability resolves.