Cheapest priced copy (Throne of Eldraine): $0.35 at Card Kingdom, near mint, their price list as of .
Wildwood Tracker 
Creature — Elf Warrior · 1/1 · Common · Throne of Eldraine · #183
Whenever this creature attacks or blocks, if you control another non-Human creature, this creature gets +1/+1 until end of turn.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Throne of Eldraine | 183 | Common | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 4 October 2019If you don't control another non-Human creature immediately after Wildwood Tracker attacks or blocks, its ability doesn't trigger at all. If you don't control one as the ability resolves, the ability does nothing. It doesn't matter whether you control a non-Human creature in between those times, or whether you still control one later in the turn.