Hellobee Boards

I got these for D after reading reviews. They were well-reviewed and so far have worked out great for him. https://www.amazon.com/dp/B00AXE9YD2/ref=twister_B01DMHPT3U?_encoding=UTF8&psc=1

We went with these, and so far we love them.

Olio Wireless Bluetooth headphones for kids - Green https://www.amazon.com/dp/B01JHDK4P6/ref=cm_sw_r_cp_api_O2-rzbM7CJ537

I went with the Bluetooth because LO used to always screw around with the cord when he would wear my ear buds and then he'd get mad when they fell out of his ears 🙄 The extra $$$ was well worth it for us. He loves them and they stay on!

We used to have the ones that Littlebug posted and they worked great. Until my oldest pulled the cord apart and broke them.
For Christmas we gave my boys these:
https://www.amazon.com/dp/B00HX0RTMC?psc=1
Definitely more money, but so far so good. And I like the fact that they don't have to contend with any wires getting tangled up. They tend to only use them in the car for longer trips (which is about 1x month), otherwise I keep them in the storage bags that come with them and out of reach so they can't get damaged.
At the time Neiman Marcus had them in stock online and had 14% cash back with ebates so it made the $50 price tag a little easier to swallow!

We had the Kidz Gear ones that fold but found that the foldability actually made them harder for DS to put on himself. When they ended up breaking, we bought a pair of kids headphones we found in-store at Walmart (can't remember the brand but can check when I get home if you are interested though they are nothing special) and found that they were much easier for him to manage himself because the ear portions didn't fold when he was trying to position them on his head. Just something to keep in mind...

We have these (Snug Play) from Amazon and have used them for a little over a year now with our almost 3 year old. They have the volume limitation that was important to me, are adjustable, and the cord seems pretty indestructible (and is detachable in case she yanks her head or whatever).

I think you can also connect multiple pairs of headphones so kids can listen together, but we haven't used that feature.

https://www.amazon.com/gp/product/B01A5RKT6C/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

These are the ones we have. I guess they do fold but they are much easier for a kid to put on by himself than our prior ones. https://www.amazon.com/Audio-JBuddies-Limiting-Headphones-GUARANTEED/dp/B00KTCMJMQ?th=1&psc=1

Not sure if it's too late, but I saw this article and thought of this thread. http://thewirecutter.com/reviews/best-kids-headphones/ They have picks for a few different price ranges and tested the volume limiting feature on a bunch of different models.