Pat the scallops completely dry with paper towels and remove the small side muscle if attached. Dry scallops are essential for a good sear.
Preheat the Blackstone griddle over medium-high heat (about 375–400°F) until very hot.
Season the scallops on both sides with salt, pepper, and garlic powder if using.
Drizzle the oil onto the hot griddle and spread it into a thin layer.
Place the scallops on the griddle with space between each one. Sear undisturbed for 2–3 minutes, until a deep golden crust forms.
Flip each scallop and cook 2–3 minutes more, until golden on both sides and opaque in the center.
Clear a spot on the griddle (or use a small pan) and melt the butter. Add the minced garlic and cook about 1 minute until fragrant but not browned.
Remove from the heat and stir in the lemon zest, lemon juice, and fresh herbs.
Spoon the lemon-herb butter over the scallops. Garnish with extra herbs and serve immediately with lemon wedges.