I feel like this was one of the original selling points of Google's ads. They were pretty simple, unobtrusive, mostly text, ads.
One of the original factors in the rapid uptake of Chrome was believed to be that the ads for it were the first time an ad appeared on google.com.
[1] https://googlepress.blogspot.com/2000/10/google-launches-sel...
Google News: https://web.archive.org/web/20021001073516/http://www.google...
Google Calendar: https://web.archive.org/web/20060831050142/http://www.google...
For comparison, Chrome: https://web.archive.org/web/20080904192205/http://www.google...
Now admittedly the Chrome one is a bit flashier. Although I haven't exhaustively gone through every homepage variant before Chrome, so it's possible there was something as flashy before Chrome as well.