I am always leery when I share these sorts of things because it is a fine line between giving young people ideas and informing parents about some of the apps that are available these days.
A new trend is something called 'Ghost Apps'. These are apps that appear to do one thing but do something much different.
Here is an article and a video that you should read and watch with your child to become aware of these sorts of apps.
The best way to make sure your child isn't accessing these sorts of apps is by looking at your child(ren)'s devices to see what types of apps they are using and who they are communicating with on a regular basis.