In Google Meet, you can replace your background with one supplied by Google, or even upload your own.
This feature is now available in both Google Chrome and the Android app.
You can also upload your own images to use as a background.
Using Chrome on desktop, you can even use a video. Google offers three videos to choose from, with more on the way. Google also plans to make video backgrounds available for mobile in the future.
Learn more about using Google Meet.