A scraper....Michael's sells several different kinds. I use it for making the buttercream smooth on my cakes. Offset spatulas, tips, bags, etc. Autumn Carpenter and Liz Marek also have beautiful books full of pictures on cake decorating and I use these as resources all the time. If she wants to try using fondant on her cakes, a silicone rolling pin and a mat to roll it on are great tools. Google " cake decorating, The Mat" to see what I mean.....it is two large sheets of heavy plastic that you can roll fondant in between and is a vital tool for me when rolling fondant. For fondant work, various cutters, molds, smoothers, etc are also vital tools. As others have said, go and look in the cake decorating aisle and just explore.