That's how you need another shelf built

Homebox and its QR Codes with a brief description on the labels would be my go-to. It'd save regularly replacing labels any time something is moved or tossed. I'm using it just to track my tools so far. I define locations (basement, shed, truck, tool cart, tool bag), and assets (long nose pliers, scan tool, cordless ratchet), and assign those assets to locations. Locations can be sub-locations of another location; so my tool bag could be in my truck or it could be in my basement. I've got a handful of tools tagged as "road kit." When I take them from my cart and put them in my road bag, I search that tag, select all and bulk update their location from the tool cart to the bag (and the bag's location from the house to my truck). As long as I'm not lazy about updating I can always find where I last left any tools.

For containers I'd create a location for each tote. Homebox automatically generates QR codes for them. I'd run those onto labels a la "QR, Tote 1, Lego", "QR, Tote 2, Random Cables," "QR, Tote 3, Xmas Decorations" and so on. A quick scan of a code pulls up that tote's page in Homebox to see the exact contents. The most tedious part is taking the time to actually organize and catalog all your existing assets. I'd put it up there with using Picard or Beets to work through a massive digital music collection - it takes a lot of initial time but adding new things later is fast and the payoff is meaningful organization.

So many holes, so little time!