If you happen to own or have access to a 3D printer, the following addons might be of interest to you.

• Bitcraze Crazyflie frame: A protective frame that attaches to the motor mounts of your Crazyflie and includes some safety loops to protect the propellers. Also allows to mount the battery beneath the Crazyflie thus lowering the center of gravity. Weighs around 3 grams.
• Bitcraze Crazyflie washer: A small washer to use to protect your motors from depressed-bearing-syndrome. Print 4 of those.
• Crazyradio housing: A small case to house your Crazyradio so you don't have to handle the blank PCB all the time