With spokes, the best thing to do is buy all the spare sizes you need, then blu tack them into your bar end plugs. That way if you have multiple bikes you’ll always have the right spoke (rather than casrrying 4x n spokes in your pack, where n is number of bikes). Ditto quick links taped inside brake levers, brakepads and mech hanger between saddle rails, tube taped to seatpost/frame.
About the only stuff I need to carry on my back now on short rides is a CO2 inflator and a mutltool. Longer rides I’d still take a more coprehensive kit with cables, zip ties, pump, first aid (plus space blanket), etc. But keeping bike specific stuff on the frame makes life easier.