I recently was looking at this for my partner. The best two options I've seen so far is the Withings ScanWatch (actually the ScanWatch 2 I think was recently released) and the Garmin Vivomove Trend. I don't have direct experience with them but from my research they seem decent. Of course they have limits compared to a full smartwatch.
I had a Withings for a couple years and ended up frustrated with it. The tiny screen meant that many notifications took so long to read I often just got my phone out instead. But the worst thing was the lack of a "find my phone" feature.
I switched to the Garmin Vivomove and have been very happy with it. It looks fantastic IMO, the transflective screen is big enough to be useful, and it has only the features I want. The only downsides are that the Garmin Android app is not as well designed as the Withings app and the battery life is only 4 days or so instead of a week, which feels like an awkward amount of time.
