Hmm... let's see:
1 primary development / daily use laptop
1 old laptop which is relegated to a place on my desk where I sit to study math or whatever
1 old laptop which is dedicated to my electronics bench, usually just used for playing music and/or looking up datasheets
1 old laptop in the bedroom, connected to a big display, used as a "media center" of sorts.
1 raspberry pi, running retropie, for gaming
1 raspberry pi, for random stuff
1 old server that's mostly idle now, but it does serve as sort of a "jump box" for ssh access from outside. It's the only box I port forward to from the edge router, so I can shell into it and then access other machines.
1 Android tablet
1 Nook (which is basically just another Android tablet)
1 Android phone
1 Atari 800 that I scored on Ebay last year. Haven't even powered it up yet, so not 100% sure that it works, but it was sold as "in working order" so fingers crossed.
1 Arduino Nano 33 IoT which provides wireless control of a couple of lamps (using a relay) that are on top of a bookshelf and hard to reach. I set this up so I could turn them on and off via http requests and put a link to the page on my phone's home screen to make it nice and convenient to control them from the phone.
So yeah... about 12, or whatever that adds up to. I have other rPi's that aren't normally powered up, and a couple of older PC's that technically still work (as far as I know) that just aren't ever powered up for anything and should probably be thrown out. There are also plenty of Arduino's in my parts box, a couple of Beaglebone Black's, and I have a few unused Android phones, including a Pinephone that I bought but haven't set up for use yet.
Edit: since someone mentioned calculators, I might as well add (heh, heh) those in as well.
I have a Sharp EL-506A, a Casio graphing calculator that I forget the model number of (FX-7700g or something close to that, I think), a TI-85, a couple of TI-86's, a couple of TI-89's, at least one TI-84, and an HP-49g.