For the filling: Beat the cream cheese and powdered sugar in the bowl of an electric mixer fitted with a paddle attachment on medium-high until creamy and smooth, about 2 minutes.

Place the chocolate in a small microwave-safe bowl. Microwave in 30-second intervals, stirring in between each, until the chocolate is almost smooth with some unmelted bits remaining. Remove the chocolate from the microwave. Stir until the residual heat fully melts chocolate and the mixture is smooth (microwave an additional 10 seconds, if needed).

Add the melted chocolate, graham cracker crumbs, pumpkin puree, pumpkin pie spice, ground ginger, and salt to the cream cheese mixture, and beat on medium until evenly combined and smooth, about 2 minutes. Cover the bowl and chill until the mixture is cold and firm, for at least 2 hours or up to 1 day.

Line a baking sheet with parchment paper. Scoop the pumpkin mixture into about 1 ½-teaspoon portions and roll into balls with your hands. Place the balls on the prepared baking sheet. Cover and chill until firm, about 1 hour.

For the coating: Place the white chocolate in a small microwave-safe bowl and place the dark chocolate in a separate small microwave-safe bowl. Microwave in 30-second intervals, stirring in between each, until the chocolate in both bowls is almost smooth with some unmelted bits remaining. Remove the chocolate from the microwave. Stir until the residual heat fully melts chocolate and the mixture is smooth (microwave an additional 10 seconds, if needed).

Working with 1 pumpkin ball at a time, skewer the ball with a toothpick and dip it in the desired chocolate, turning to fully coat. Allow excess chocolate to drip off and return the ball to the prepared baking sheet, using a second toothpick to carefully slide out the skewered toothpick. Sprinkle the truffle with the desired garnish while the chocolate is still wet. Repeat the process with the remaining pumpkin balls.

Chill the truffles, uncovered, until the chocolate is set and hardened, about 20 minutes.