The Nintendo 3DS is presumably (with over 75 million units sold) the most popular camera that takes 3D photos in the MPO format. Unfortunately, the original 3DS's cameras are rather poor: absolutely dreadful dynamic range and tons of color noise. However, they did improve the cameras on the New Nintendo 3DS, which I've never owned. I've even considered making some homebrew to apply computational photography techniques on the 3DS to reduce noise and improve dynamic range, but I'm not at a point in my life where I can justify that right now.

I was looking at my old 3DS photos just recently, and there's not much software to read MPO files, so this project looks pretty darn cool and I'll be checking it out.

Something that I'm sure some people aren't aware of is that the 3DS's 640x480 photos don't match the resolution or aspect ratio of the 15:9 400x240 (800x240, but halved horizontally for 3D) screen, so the 3DS photo gallery actually shows photos zoomed in by default. If you didn't know this, now you can revisit your 3DS photos and see extra photo for free by pulling down on the circle pad.

Edit: I should mention - I did say that there's not much software that reads MPO files, but one program that does is StereoPhoto Maker. https://stereo.jpn.org/eng/stphmkr/index.html I haven't tried it out yet, but it supports aligning and batch-processing 3D images, among other features.