I have two old iPads and an old iPhone in my stack.

The iPads are HomeAssistant Dashboards for me. One connects to a VNC server on the HA host, as the browser is too outdated to properly display the dashboards. The other uses the HA app, and can render just fine.

The iPhone is jailbroken, and used as an AirPlay relay server. Connected via Bluetooth to a speaker, MusicAssistant keeps the audio from the aux on my Mac Mini and the audio streaming to the iPhone in sync, creating surround sound audio.

I use an old iPad as a digital photo frame. Sits on a horizontal cupboard top in £3 Ikea wooden phone stand, powered by a right-angle Lightning cable from ebay. Selfie camera is covered with a glossy black privacy sticker, also from ebay. It works tolerably well.

https://www.techradar.com/how-to/how-to-turn-your-ipad-into-...

The iPad 2 can be downgraded to iOS 6.1.3 or 8.4.1. Both offer better performance than iOS 9 and have untethered jailbreaks. Once downgraded and jailbroken you can sideload hours and hours worth of games. A lot from that era are IAP-free.

I use an iPhone 5 downgraded to iOS 6 (tethered) as an iPod. I love how I can unplug my headphones from my work Mac, plug directly into the phone (no adapter required!) and it effectively mutes Slack without actually muting it. Syncing with the latest version of iTunes still works, albeit slowly.

I also use an iPad 4 (tethered to iOS 6) as an ebook. iBooks works great and I love the pseudomorphic design.

See also: https://github.com/LukeZGD/Legacy-iOS-Kit

Tried to offload to a friend with a 3 year old and not much money. They threw it out and bought an iPad Pro for the little one.