Don’t get any light with small removable parts that the kid can unscrew and eat. Especially small batteries, which can be fatal if swallowed. Sofirn C01S that someone suggested is nice for an older kid but 3yos still try to eat stuff like that.

I don’t know if there is still such a thing as a “shake light” but if you can find one of those that is completely sealed, it might be a good choice. Those lights are powered by a moving magnet and capacitor inside, so it will charge up when you shake the light like a rattle for a few seconds, and run for a minute or so until you shake it some more. There are no removable parts, no batteries to recharge, etc. So I always thought they’d be a good choice when this question came up on other flashlight sites.

Keep the lumen level very low. Even a 1 lumen led can be very bright, maybe unsafely so, if you put it right up to your eye. Maybe defocus the beam by scuffing the led up with sandpaper.

There used to be 5mm leds with swirling colors like distro strobe lights. Something like that could be fun.

Added: what about one of those bigger lights that you power by turning a crank? Again you’d want to exoxy down any part that can come loose.

I have some Sofirn C01S for my kids. AAA, sturdy, not too bright, rotary.

Sadly, not available anymore.

None of my little ones have thumbs, however I’ve seen others recommend the Convoy T3. Uses AA battery, comes in a lot of colors, inexpensive, and if you turn off mode memory and set it to group 9 it will start at 50% brightness and won’t be able to get any brighter than that.

My 4yo nephews likes to play around with one of my zebralights. They can be programmed to only have specified brightness levels available and last for months on low lumen level (depending on battery and brightness level obviously) But they are a little expensive

I usually suggest a TS10 with a reduced ceiling.

For a 3 year old, I might suggest an IKEA JLUSA. It’s a light with no batteries. Instead it has a hand crank to provide light. They market it as a kids toy. My kids had one when they were younger. Just went to look, and it seems like it is discontinued in the US, but is available in other countries. Depending on where you are maybe this is an option.

Mine love the Ledlenser kidbeam4 (I use nimh), it has high white, low, RGB and police strobe. Sometimes like to play with an AA minimag.

Convoy T3 with Nimh cell and set it to 50% output and start on low. Great LEDs and available in bright colors as well.

Thank you all for your thoughts. I found this one by varta https://www.amazon.de/Varta-lippenstiftförmige-Taschenlampe-Handtaschenlicht-Schlüsselanhänger/dp/B00TSXLQ0S/

Handle glows in the dark and it outputs 19 lumen according to varta. Sounds low, but I’m aware it still requires supervised use. Which is fine I think. Swallowing parts isn’t much of an issue, the kid isn’t big on that. I’ll see if I can find it in a store so I can try how hard the button is to press