I had two portable DVD players, both of which were designed to open up like a laptop. The first one was a pink Polaroid brand player that my older brother got for Christmas back in 2004, it was our first dedicated DVD player (our first computer with a DVD drive was my mom's old laptop, which we got a couple years prior) and I remember the last movie we watched on it was Tinkerbell in 2008/09. We got rid of it not long after that.
In 2018, I bought a silver Audiovox portable DVD player at a local Goodwill for $20. Its battery was dead and it didn't come with an AC adapter, so I had to buy an AC adapter separately on eBay for about $10 extra. I didn't use it frequently, though the one advantage that it had over our home DVD/Blu-ray players (barring a JVC DVD/VCR combo which is in need of repair) was that it could play PAL DVDs, though I don't remember if it could play DVDs with regions codes other than 0 or 1. Its AV output jacks doubled as an AV input (which can be toggled by a slide switch on the side), so it could also be used as a video monitor. Its screen backlight died the last time I tested it a couple years ago, so I had to get rid of it. I probably could've modified it to use LED strips for a backlight, but I didn't have the time to dive into that.
I hope to find another portable DVD player at a local thrift store the next time I go to one, even though I doubt I'll find myself in a situation where it would be necessary to use one anytime soon. I heard the later Sony models were desirable since they had a higher resolution screen than most other players, and I heard they also made portable Blu-ray players.