After showing up for both the Play Store and Gmail recently, the latest Google apps to get dark mode are the Google app and the Google Assistant. This rollout will be the second time Google rolled out the dark theme for the Google app after a select number of users got it back in June. But this will be the first time Google Assistant will be getting this option. A server-side update is bringing the dark theme to some users, so expect to wait for a bit before it becomes widely available. The update is reportedly showing up for users in the US, the UK, and Australia.
And interestingly enough, it's also showing up for some Android Pie users. It allows them to choose between light and dark themes or to have it switch automatically when Battery Saver is enabled. One thing Android Central noted is that the Google Podcasts service within the Google app still has the Material White theme.