Ultra-Mini Wireless Microphone That Seamlessly Conceals into Your Outfit. 30-Hour Battery Life, 984ft (300m) Range.

As far as small on-camera flashes go, I was actually pretty impressed with the iM30. Small yet powerful, and good for beginners too.

Godox Cube-S 2.4GHz Wireless Microphone System: Stylishly tiny mic that works a treat ...