Cake Ball Mix-ins

I love trying new cake ball combinations.  I pick the cake flavor, the frosting flavor, and the candy coating flavor.  Sometimes I try mix-ins.  I've tried coconut and I've also tried peppermint chips (peppermint-flavored white chocolate).  The mix-ins add a kick of flavor and can also add color, texture and moisture.  Other mix-ins I might try are mini chocolate chips and toffee chips.  I also think it might be fun to have a mini marshmallow at the center of a cake ball.