The iPod Video and lower had some pretty incredible tools and firmwares available looking back. I was part of the iPod Wizard team (mostly helped with mapping hex locations on new firmware releases and created a handful of themes, including backporting the color themes to the 4-tone generations) and contributed a bit to the iPodLinux project. At one point, I had a bootloader that let me switch between the normal firmware, Rockbox, iPodLinux, and iPod Wiki (all of Wikipedia viewable offline on your iPod) available just be restarting my iPod. It was a dumb smart phone half a decade before the iPhone.

The devs on those teams really pushed that little MP3 player to do things it was never intended to do.