I have a couple of 40l Samla boxes from Ikea - the Really Useful ones are sturdier though and I may invest. Handy that they are see-through though.
I also have a 22l Samla, and the insert that is like a cleaner's caddy - I use that for the kitchen utensils, oven gloves, roll of bin liners, matches (I keep those in a plastic tub with a couple of silica sachets to keep them dry), a 100ml squeezy bottle (from Muji) filled with washup liquid, etc. A roll of washing line, handful of pegs (for washing or for closing food packets - they are dedicated to the camping basket and kept clean), duct tape, some ziploc bags, washup brush, washup scrubber, pair of rubber gloves. Salt and pepper (I bought a glass jar which has a twisty mill on top from the supermarket - just for camping/SC). A Ziploc wth a few sachets of ketchup (scavenged from McDs etc) and things like mayonnaise, mustard, soy sauce etc if I can find them, as well as a couple of stock cubes and some sugar sticks (also often scavenged from coffee shops). A couple of pocket packs of tissues. Some spare batteries, maybe a couple of nightlights. My 3 kitchen knives are all good sharp ones but each have covers on the blades so can get thrown in amongst everything without fear of stabbing yourself when rummaging. A small Ikea chopping board. My "really useful bits" box. The caddy has been useful for carting things around.
I have a mat inside the door after a memorably mucky Cub camp!!!I keep croc flipflops there too, and pull off my boots as I go into the tent. If you don't have a mat, if you bring your food in a big cardboard box from the supermarket and then fold the box out flat, you have a ready-made and easily recyclable mat for a couple of days. Just make sure there are no staples!
We have a 10l square container for water - I try to send DD off to fill it as part of keeping her busy while I cook dinner. Then it is full for washup (maybe), cups of tea, after dinner. And as it gets dark, I put my headtorch around the canister and point it inwards - this magnifies the light to make a useful general light in the tent or on the table - just enough to read by if right beside it, but plenty to provide ambient lighting for the area.
I use the sort of swim bags that have a drawstring around them that you can put on your back for my wash gear - holds my towel, washbag, clean undies etc and is fine getting wet when coming back, and is easy to hang if there are any hooks or over the corner of the door. (Although a few s-hooks would be a useful addition too). We have a bunch of decathlon and other sports/travel towels, they are great!
I do the filling a thermos as well - on Cub camp, a cup of tea before facing feral Cubs at stupid o'clock in the morning is vital!! So when we make the last cup for leaders (at stupid o'clock at night!) as the Cubs finally settle down, I take out the jug and fill my flask as well (and my hot water bottle for my sleeping bag) before we turn off the gas to the burco. And when camping with DD, I use it for tea overnight, but also for any leftover hot water whenever we boil the kettle for later washing up etc.
Another Cub leader uses the big blue Ikea bags when camping as a family - each person gets a bag and keeps their stuff neat in it but its large enough to easily rummage in for smaller people, and can be stuffed into the car at the end.
I wear thermals for sleep under my pjs. (And a hat on my head!). I put the thermals on after dinner as the evening is starting to cool, and put my clothes back on top. That means that when I am changing into pjs at bedtime, I am not getting freezing cold right to my skin but keeping one layer on and keeping that heat in. Made a big difference when I copped that one!