Friction levers. You can still get them! I built a touring bike with them because they’re comparatively cheap and very easy to maintain. They’re indexed (click into place at the center of each sprocket) but you can disable this feature quickly if you need to, which is nice if you’re forced to use a different cassette or there’s an issue with your cable.

I absolutely love them. They wouldn’t work on a racing bike where you need to shift quickly without taking your hands off the bars but for a commuter or a touring bike they’re ideal.