Knives and chisels are basically needed for this type of project. You can use just a normal knife if you wish and there is absolutely nothing wrong with that!
But if you choose to upgrade your game id say give the Xacto X5175 Deluxe Wood Carving Set a fair shot. This set contains No. 5 knife with No. 24 Deburring Blade, No. 18 Heavy Wood Chiseling Blade, No. 19 Angled Wood Chiseling Blade, No. 22 Large Curved Carving Blade, No. 26 Whittling Blade, and No. 27 Heavy-Duty Saw Blade, five gouges, and four routers boxed in a wooden chest.
I mean what else are you really going to need? Its an all in one package!
Feel free to tell me what you have made in the comments!