Sort:  

I currently have around 10 Pis.

I use one on my 3D printer for "octoprint" which allows me to print over the network rather than moving an sd between computer and printer as well as other things.

I have one on tv for RetroPie to play 8000+ games from before 2000 on 50 different consoles.

I have a Pi zero for same purpose but for the portable RetroPie I made.

I use one for my wireless controller for Ubiquity devices.

One for Pi Hole for network wide ad blocking.

I got another one on my tv as a plex client (media center viewer).

Got one attached to a camera I use from time to time for projects like time lapse.

I got one for my son to learn programming and electronics but he really just doesn’t have interest.

Then I have a few just lying around (Pi 2 my first, and a few 3’s and zeros spare).