When I went on vacation, I left my phone behind and took along an old smartphone with no sim card. I used the smartphone as a camera. It still received a GPS signal and I loaded off-line maps so I could use Google Maps. When I was at the hotel in the evening I checked my email and looked up local information with wifi and played games on it. But work couldn’t call me, which was nice.

The most common thing I’ve seen are projects where it acts like a screen or control panel on the wall. Something that’s a fixture or art project.

You don’t need it for anything like music or games - your new phone will be more convenient and run those things better anyway.

A friend of mine stuck an old tablet on the wall and connected it via Bluetooth to his keg system. It gave him a permanent status readout on his beer temperature and how much was left in each keg. It just had a power cable plugged in all the time so it didn’t need to be charged.

Bicycle or hiking computer. With osmand and organic maps you can get your position from GPS without a sim card and use the phone for navigation, trip recording, stats etc.

Load it to the brim with literature pdf’s, put in a faraday box incase an nuclear EMP or those monster solar flare things takes out all electrical components. I’m not a doomsday prepper or anything but did this with an old 256gb phone for shits and giggles. It’s absolutely insane the amount of text documents 256gb holds lol

I like having offline apps on my old android phone. Such as the Kiwix app with offline wikipedia, Organic maps app with downloaded maps, Readera app with some epub books.

In case you own a lot of devices with remotes, you might transform it into a universal remote with an USB C IR dongle. Wouldn’t be my first choice as you’d still need to recharge it so often but I read of such projects.

Alternatively, you could give it to children for gaming and watching videos. Children are anyway mostly on WiFi and if you equip it with some emulators and ROMs they’ll have tons of funny games without all of these toxic in-app purchases, ads and casino mechanisms.

Install F-Droid and IzzyOnDroid repos and you can use it for whatever you find there. I use mine as an alarm clock, note pad, music player and spare camera around the house. Sometimes a browser (wifi) but it’s a bit old. I thought about putting all my recipes in text format and using it as a cookbook as well.

I use a Pixel 6a 4a I had laying around as a dedicated Discord device, paired with a bluetooth headset. Now I can chat with the lads while around the house doing chores.

I use my spare as kind of a media controller sort of speak thanks to kdeconnect and casting locally. In the near future, I want to get into emulation so that might be what the spare phone gets used for instead with the help of one of those cheap steam deck docks for USB C. As for more creative ideas, I heard some people use them as a dedicated GPS, media player or even a dashcam for their cars (not sure how the battery would hold up in the heat and whatnot). You can use it to remote view your pc or even play games from that same pc or even one you don’t own through cloud gaming. You can repurpose it to be a 2fa device only, so you can keep your TOTPs and other 2fa methods separated from your main assuming the device is up to date security wise. If the camera and whatnot are decent maybe keep it as a spare camera for all your video/picture needs (online meetings, video recording, document scanner, etc…) a dock might be useful for that. If your spare has that desktop like experience when you connect it via HDMI there’s nothing stopping you from using it as a really lightweight computer to do basic web stuff. These are really vague answers since I don’t know what phone you have but I hope it helps get the ball rolling

Donate it. I’m sure there’s someplace that will want it as a wifi-cabable minitablet for kids to access the Internet on.

Eat it.

i have bad luck with phones so i go through them faster than most so i always the the $100 androids.

in the past i’ve used them as ip cameras as part of a homemade security monitoring systems using motion; car dash cams; car backup cameras; homemade lojack; car stereo screens; parallel parking sensor aides; secondary alarm clocks; intermediate android auto proxies; backup alarm clocks; and secondary phones for applications/control that my employers have mandated; system interface screen; bathroom readers; usb drives; wifi extenders; and remote controls.

I used a pair of them as an improvised baby monitor for a while.

You can try to see how far you can skip it on a lake or pond.

Set up wifi plus some free music streaming (not saying you should purate it, or use a web browser with ad block), hook it up to a loudspeaker and tada, modern jukebox!