Cheapest priced copy (Streets of New Capenna): $0.35 at Card Kingdom, near mint, their price list as of .
Celestial Regulator 
Creature — Angel Advisor · 2/3 · Common · Streets of New Capenna · #174
Flying
When this creature enters, choose target creature you don't control and tap it. If you control a creature with a counter on it, the chosen creature doesn't untap during its controller's next untap step.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Streets of New Capenna | 174 | Common | $0.35 | $0.49 |