Cheapest priced copy (Secrets of Strixhaven Commander): $0.79 at Card Kingdom, near mint, their price list as of .
Silkguard 
Instant · Mythic · Marvel Universe · #37
Put a +1/+1 counter on each of up to X target creatures you control.
Auras, Equipment, and modified creatures you control gain hexproof until end of turn. (Equipment, Auras you control, and counters are modifications.)
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
4 printings · $0.79 to $5.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Marvel Universe | 37 | Mythic | $4.49 | $5.99 |
| Neon Dynasty Commander | 29 | Rare | $0.99 | — |
| Neon Dynasty Commander | 71 | Rare | $1.29 | — |
| Secrets of Strixhaven Commander | 286 | Rare | $0.79 | — |
3 rulings from Wizards of the Coast
- 18 February 2022A creature with a counter on it is considered modified no matter what kind of counter it is or which player put it on that creature.
- 18 February 2022A creature that is equipped is considered modified no matter who controls the Equipment that's attached to it.
- 18 February 2022An Aura controlled by an opponent does not cause a creature you control to be modified.