Not exactly a coherent collection of a specific thing, but I like to gather older video game consoles and retro tech to hook them all up in the most interesting way possible. I've currently got an SNES, N64, GameCube, and Sega Saturn hooked up to an old decent quality CRT security monitor over s-video. I plan to get an s-video matrix to hook up all the consoles at once and switch between them easier, and I also plan to at some point add a PS2, Xbox, and Dreamcast into the mix.
I might also at some point try to find an old early 2000s or even late 90s computer and hook that up too. I don't have a lot of space, so I might have to hook it up to the TV, but as long as it can play the games from my childhood without issue, I don't care what wonky setup I need. Old games just aren't as fun on an LCD.
I do probably need to degauss the CRT though. When I first picked it up it looked fine, but I ran a metal fan a little too close to it for too long and now it's got distorted geometry on that side.
So I suppose I collect retro electronics. I don't even collect games for the consoles I own. I just bought them for the fun of hooking them up.