After releasing my first app, Peek-a-Zoo in 2011, I reused the code and released 4 followup up apps to extend the series (Peek-a-Zoo Underwater, Peek-a-Zoo Train, Peek-a-Zoo Farm, Peek-a-Zoo: The Collection), many of which were feature by Apple in various categories. I also reused the code to create a similar series aimed at infants. When the App Store came out with 'Bundles' I created bundles for my different series.
At the end of 2014, I hit over $100K in revenue for the first time.