China-based OLED producer Visionox demonstrated a beautiful rollable OLED prototype:
We don't have any information about the display, but the demo looks great - complete with a notch in the OLED (not clear if that's just part of the image displayed, though).
Visionox has recently demonstrated and even started to produce cutting edge OLED displays - for example for Xiaomi Visionox provided a flexible OLED display that is wrapped around the complete smartphone, a tri-foldable OLED display and an OLED that has an embedded camera behind it.
Visionox is currently operating a 6-Gen AMOLED production line in Hebei (with a monthly capacity of 30,000 substrates) and has announced plans to establish a similar flexible OLED line in Hefei in a $6.3 billion investment. In August 2019 Visionox announced plans to establish a new flexible and foldable OLED module factory in Guangzhou, China.