Discord app version 9.8.2 on Android features a hidden AMOLED dark theme.
Found by XDA Developers, the update optimizes the app for handsets with an AMOLED screen.
To find the new mode, navigate to ‘Settings,’ go to ‘Appearance’ and then tap on ‘Dark’ ten times. You’ll then receive a notice that says “Brave one, the path to darkness opens!”
Now, the AMOLED optimized mode will be below the ‘Light’ and ‘Dark’ options. This version should be blacker than the previous ‘Dark’ theme.
This feature isn’t restricted to Android 10 devices and also isn’t a part of the operating system’s system-wide dark mode.
The AMOLED dark theme is also not available for every part of the user interface.
Source: XDA Developers