I need my current road bike, my trainer bike (which doubles as a spare road bike, so I need the rear wheel too), and my mountain bike (really just goes on gravel trails). Could get rid of the ancient e-bike I haven’t ridden and a few extra wheels. I have one spare tube for each size plus two extra for the road bike (that I ride all the time), and I wouldn’t feel comfortable with less. I probably could ditch the tubes that only work in the old road bike (though I did blow a tube on the trainer and used one). I have a bunch of parts I could get rid of – spokes, old tires, old bits of chain, most of a 9-speed and 11-speed group, handlebars and seatpost from an old bike, some old chainrings, etc. I’m wouldn’t give up any tools, though I don’t have anything like a full set.
For kit I have a few old jerseys I should toss but the stuff in rotation basically makes up a laundry cycle.
For training I’ve got a trainer, a mat, a fan, a towel, and a table. TR is provided via my phone and entertainment via my tablet, so nothing extra there.
I’m not trying for minimal so I’ll be keeping most of this, and I’ve also thought of trying to obtain a frameset and build another bike from some of the spares but that’s crazy thoughts.