English: A rough sample of the OnePlus Slate typeface. The typeface was presumably commissioned by Rod McDonald of Monotype Imaging in 2017 as alternative font to Roboto. OxygenOS users can select this font by going to Settings -> Fonts -> OnePlus Slate™.

The typeface has 6 weights (Thin, Light, Regular, Medium, Bold, Heavy) and much like Lucida Grande lacks any oblique or italic styles. I have demonstrated both the Medium and Bold weights in this sample. The red colour was taken from their current logo.

The glyph design, in particular the lower-case a reminds me of Prelude (or Apres as it is now sold by Font Bureau) for the Web OS devices.

Contrary to rumours I saw around the Internet regarding the licensing, it seems to be a proprietary typeface and there's no evidence to support this design's fonts being open-sourced.