To make one set of 10 truffles, finely chop the 4 ounces of semi-sweet chocolate and place in a heat proof bowl.
In a small pot heat over medium heat, bring the heavy cream to a simmer. For only the orange truffle add orange zest to the cream before heating and allow to infuse while heating.
Pour heated heavy cream through a sieve onto the chopped chocolate and let sit for one minute.
Stir the chocolate and cream until mixture becomes homogeneous. Add ingredient from the filling addition list for desired truffle and mix into the ganache (except the orange zest).
Cover ganache with plastic wrap and refrigerate for about one hour.
Repeat steps 1-5 for each desired truffle type.
Once cooled, roll a scant tablespoon of ganache into a ball to form the truffle filling.
Melt the chocolate for dipping over a double boiler and, with the ball of ganache laying on top of a fork, dip the truffle filling into the chocolate. Tap excess chocolate off before place on a baking sheet and allowing chocolate to set before topping with the associated truffle topping (except orange truffle, see following step).