What is the best everyday “mundane” item in D&D? Haha! My first instinct is to say gold, but I’m not sure that counts as an item. No, not really actually. Not unless you were carrying around a nugget of gold ore.
For this question I can actually name a couple of items that are very useful. Rope, being one of them, and torches being the other. However, I’ve become rather fond of things like soap. Always nice to not smell bad when looking for your next job-even if you’re a mercenary.
The reason I make this claim is because these are items that ALWAYS! get used. Are they the best? Who knows…Are they incredibly useful? Hell yes!
I don’t think I’ve ever played or run a campaign that didn’t require some form of light or a rope. I’m not exaggerating either.
It’s hard to imagine a player not making it a point to have torches for a character in a game that has the word “Dungeons” in the title. I mean, its pretty clear the kind of stuff you’re going to need. A source of light is chief among them.
Why not things like horses? Not always useful, not affordable at low-levels, and not always used. Often, players like to have their characters walk everywhere, or hire transportation. Owning a horse can be a bit inconvenient, as weird as that might sound.
Scaling walls, being able to see, and keeping oneself clean are essential ideas. In real life (especially in real life), cleanliness is valued. Scaling walls, not so much. Especially with cubicles. I doubt a co-worker would care to see a grappling hook come flying over the barrier. Although, it might be worth a good laugh.