I've been interested in this subject for a while and have a few recommendations.
Stanley Thermos. It could get hit by a fucking train and would still outlive you. Don't recommend putting cofee/milk products etc in them though because it will make the gasket smell. Excellent water container though.
Double edged straight razor. The handle piece is virtually indestructible. I bought a package of like 500 blades for like 30 dollars and haven't had to buy new ones for actual years. Fun fact as well, once you learn to use one it's better for sensitive skin because you're only dragging one razor across your skin per stroke instead of 5 or 7 or whatever the fuck the "better" ones have. Can confirm the "more blades = better" shit is just pure predatory marketing.
Buck knife. Multi tools are cool but if you tend to use the knife often, invest in a higher quality knife and stones to sharpen it. Sharpening stones (not the crap ceramic stuff they try to sell) will last a lifetime and will also keep all your kitchen knives beautiful for years. While you're up to it, get a piece of raw leather, like the back of of an old belt, and use it as a strop to polish off the blade when you're done sharpening, it really does make the cut smoother.
People say Mag light, but I'd personally recommend Olight as well for flashlights. The Olight Baton 4 is a ~600 lumen adjustable brightness flashlight with strobe which will blind you if you aren't careful and its smaller than a pill bottle and comes with a reversible clip and inset magnet in case you need to stick it somewhere to keep the light steady.
A graphite metal "magic" pencil. Instead of using normal graphite, these metal bodied pencils have end pieces you screw in as a tip, are erasable, and one nib takes forever to run out, something like 5 pencils. They dont draw as dark as a regular pencil due to the hardness but for general usage they are handy.
Mighty plugs ear plugs. Want to know what it's like to be deaf? Buy these. They aren't too costly, completely seal the ear, and I only have to get a new package once every few years. They're so effective I had to purchase an alarm clock built for deaf people which shakes my mattress instead of making a sound because I couldn't hear any normal alarm clock after I started using these. This combination is unbeatable if you have awful neighbors or live on a busy street with night traffic.
Any self winding watch. Stop fucking around with button cell batteries and evolve. If it's cheap, that's probably better, if it gets scratched you don't have to care. Seiko is a good brand in my experience.
If you're into camping get a decent mid sized carving hatchet. I have a mid sized Hultafors swedish steel one. People like splitting axes because they do what they're advertised to do, but theyre huge, heavy, and you cant carve or skin with them. A lighter smaller carving axe will do the same job splitting a log if you baton it with a medium sized stick. If you need something bigger to cut down a tree, go for a curved folding saw to bring with the hatchet. The Silky Saw Big Boy is great for that. Also buy a wool blanket. That shit will keep you warm in -35 C if you use it correctly. Also tents are neat but cumbersome, instead invest in a tarp and learn to make a lean to/other tarp configurations in combination with a ground sheet. If you expect you'll be facing inclement or extremely wet weather, get an oilskin tarp (or make one yourself its literally just a cotton sheet which you have ran through a few dryer cycles as hot as possible, and then soaked through in a 50/50 mix of boiled linseed oil and mineral spirits and hung outside until completely dry. Don't put an open flame near it at any point in that process).
I probably have a bunch more, but can't think of them off the top of my head.