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 protective frame that fits around the display and allows mounting it to any flat surface using two screws. Please note that the connection pins have to be removed and replaced by cables soldered to back side of the PCB (this is very easy).
It is EXTREMELY important to clean up the surfaces of the front that surround the glass area of the display. If anything protrudes or the opening is just a fraction to small, the display will crack when you try to mount it. The display will then instantly become useless. If you take your time you will be fine.
I have designed an alternative holder that makes it possible to mount the display directly on top of the flight controller. That version uses the standard 30.5 mm hole pattern of the CC3D/Naze32 boards. It can be found here: