Depending on what type of activity/operation ( LE, Military Ops, SHTF )your plate carrier is set up for, you can add all types of gear to it. Some of the items you listed would fit in my third line gear category( backpack ).
If you have room and space available then here's few ideas depending on your situation;
Deep Woods Off 1 ounce pump sprayer works for me and hasn't leaked
Micro LED Light ( Photon type )
Flex Cuffs
Flex Cuff Cutter
Primary weapon spare parts ( M16 firing pin, gas rings, hammer pin, FP retaining pin, extractor, extractor spring, safety detent and spring)
Spare bulbs for weapons light and hand held light
OC Spray
Granola bars ( or energy bar )
Caffeine tabs or caffeinated drink mix pouches ( Sparks works for me )
Batteries for all weapons lights and optics
Small roll ( 5 yards ) OD or black Duct Tape, or roll electrical tape
Blow out med kit
Lens Pen ( Weapons optic cleaning pen )
Full-Auto