Most feature phones (simple phones with physical buttons) typically run on alternative software such as KaiOS. However, a blogger has posted a video of what appears to be one of these devices running Android. This phone, linked to the brand Nokia, may be released with a ROM based on an older version of this OS: Oreo (8.1).
https://www.notebookcheck.net/New-leak-alleges-the-development-of-a-Nokia-feature-phone-with-Android.435101.0.html