Like Centaur from Ravnica, Satyrs are NOT Humanoids. They are Fey instead of Humanoid. The most obvious interaction would be with the spells like Hold Person. Since they are not Humanoids, Centaurs and Satyrs are not valid targets for Hold Person.
Any spell or ability that specifically says it targets humanoids would not work on them (Hold Person), but those that target Fey will (Protection from good and evil). There aren't a lot, but they are important distinctions.
What exactly does this impact? They're still humanoids, so...? Protection from Evil and Good comes to mind.
Blood Frenzy. The quipper has advantage on melee attack rolls against any creature that doesn't have all its hit points.
Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 1 piercing damage.
Like Centaur from Ravnica, Satyrs are NOT Humanoids. They are Fey instead of Humanoid. The most obvious interaction would be with the spells like Hold Person. Since they are not Humanoids, Centaurs and Satyrs are not valid targets for Hold Person.
Oath of the Ancients Paladins can turn Fey.
Any spell or ability that specifically says it targets humanoids would not work on them (Hold Person), but those that target Fey will (Protection from good and evil). There aren't a lot, but they are important distinctions.
Protection from Evil and Good could be used to keep them at bay