Cheapest priced copy (Foundations Jumpstart): $0.35 at Card Kingdom, near mint, their price list as of .
Yarok's Wavecrasher 
Creature — Elemental · 4/4 · Uncommon · Core Set 2020 · #81
When this creature enters, return another creature you control to its owner's hand.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Foundations Jumpstart | 395 | Uncommon | $0.35 | — |
| Core Set 2020 | 81 | Uncommon | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 12 July 2019If you control no other creatures when the triggered ability resolves, you simply don't return anything. There's no penalty for being unable to do so.