I have a Palm Pilot V along with charging cradle and data transfer cable, must be at least 20 years old but I haven't fired it up for a number of years, but pretty sure it will still power on and I have installable software files in my archives.
I have an old tower PC with Win 2K installed, last fired it up maybe five years ago. I also have a rackmount generic PC from 2005 which works fine, running Windows XP.
Compaq Presario notebook from 2005, with Linux Mint installed now, built like a tank, cost almost $1,300 in 2005 with 512MB RAM.
I have my Samsung feature phone (slider with full QWERTY keyboard), it boots up just fine but no longer connects to anything with the end of 3G service earlier this year.
I use an old iPad for running authenticator apps, not sure how old but it will no longer receive software updates from Apple.
Have a working Sony PS2 in storage, and still use a PS3 to play Bluray discs and access internet streaming.