At the moment I am making a Fritzing plan for my Raspberry Pi only quadrocopter. It takes more time than I thought it would take, because some parts are missing in the libraries. A very important library for me was the Adafruit Fritzing library, which was easy to import and contains all the Adafruit modules I own.
One part I still have to include in the blueprint are my four HC-SR04 ultrasonic range finders that I bought on Amazon. The only problem is that the range finders give 5V signals which could maybe damage the Raspberry Pi, because it normally operates at 3,3V. One simple solution is to add resistors as illustrated nicely here.