If you run Cleanflight on the Naze32 bord (or on any of the copies) you can attach one of the cheap miniature oled displays. The displays are available from eBay. The displays are convenient for displaying flight controller information before takeoff.
The oled displays are quite fragile, which is an aspect that does not fit mini quads well. It is easy enough to connect the display to the flight controller, but hard to find a good way of mounting it to the frame. If you mount a display on your frame using double sided tape, there is a high likelihood that you will snap off the unprotected lower display glass corners and instantly destroy the OLED (I have destroyed two of them).
This design is a simple holder for an oled screen mounted directly over the flight controller board using the standard mounting holes of the controller.
I have made another version that fits like a protective housing around the oled and allows mounting it to the frame with screws. It is found here: